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Class 6 Basic Science Chapter 1 Food for Health Question Answer Notes

Basic Science Class 6 Chapter 1 Question Answer Notes Food for Health

Food for Health Class 6 Questions and Answers Notes

Let Us Assess

Question 1.
Nutrients and food items which contain them in plenty are given below. Match them drawing lines.
• Carbohydrate – Leafy vegetables
• Minerals – Pulses, Egg
• Fat – Cereals
• Protein – Oils
Answer:
• Carbohydrate – Cereals
• Minerals – Leafy vegetables
• Fat – oils
• Protein – pulses, egg

Question 2.
Which is the health issue faced by a person who doesn’t eat food containing iodine?
A. Night blindness.
B. Rickets
C. Anaemia
D. Goitre
Answer:
D. Goitre

Question 3.
Our body can’t digest fibre. If so, why is it said that we should eat food items which contain fibre?
Answer:
Fibres are the cellulose obtained from plant-based food that can’t be digested by our body. Fibres are not nutrient components. However, fibres facilitate the digestion and egestion of faeces through the large intestine. So it said that we should eat food items that contain fibre.

Question 4.
Which nutrient is required for the health of teeth? From which food items do we get this nutrient?
Answer:
Calcium. From food items like egg, milk, leafy vegetables and fish, we get calcium.

Question 5.
“The teacher gave me an iron tablet today, but I didn’t eat it.” Do you agree with Aruna? Why?
Answer:
No. I cannot agree with Aruna.
Iron is a mineral. Such kind of minerals are essential for the proper growth and health of the body. It plays a major role in the formation of haemoglobin in blood. To prevent iron deficiency disease like anaemia, iron tablets are supplied in schools. So Aruna should eat the iron tablets provided to her.

Question 6.
Vitamins and minerals are required by our body in lesser quantities. Hence, it is enough to include small quantities of food items which contain them in our diet.’ This is a child’s opinion. Do you agree with this? Why?
Answer:
I cannot agree with the child’s opinion.
Vitamins and minerals are required by the body in small quantities only. However, if they are not available to the body in the required quantity, deficiency diseases are bound to manifest. In addition to that, the food items that contain vitamins and minerals may also contain other nutrients, and hence reducing the quantity can lead to many other deficiency diseases.

Basic Science Class 6 Chapter 1 Question Answer Kerala Syllabus

Question 1.
Did you notice the conversation between the mom and the doctor? Some of you have had this kind of experience. What is meant by nutritious food? Write your guess.
Answer:
Food that contains all the essential nutrients, used by our body to sustain growth and vital processes and to provide energy is meant by nutritious food.
We have a variety of food items around us. We eat different kinds of cooked and raw food items.

Question 2.
Some food items we usually eat are given in the pictures. How can we Classify them? Write down in the Science Diary.

Answer:
A. Cereals
B. Fruits
C. Vegetables
D. Pulses
E. Leafy vegetables

Question 3.
What are your favourite food items among them? Any dislikes? Why? Discuss.
Answer:
(Just for your reference)
Cereals and fruits are my favourite food items. I do not like leafy vegetables because I feel they are not tasty.

Question 4.
List the food items you usually eat in a day.

Answer:

Breakfast	Lunch	Dinner
Idli and sambar Appam and Bengal gram curry Puttu and green gram curry Upma and tapioca Egg	Rice and dal curry Biriyani and Chilli gobi Fried rice and salad Fish Curd	Soup Chapati and vegetable curry Noodles Milk

Should we eat only the food items we like? Pay attention to the conversation below.

Question 5.
Did you notice what the three children said? Will the food they like be enough for the growth and health of these three? Write down your opinion. Present in the class and explain.
Answer:
Yes. I noticed what the children said. No, the food these children like will not be enough for their growth and health. They need to eat the food items that contain vitamins, protein, minerals, carbohydrates and other nutrients. Our body needs different kinds of food items like fruits, vegetables, milk, rice, and pulses to grow strong and stay healthy. So, everyone should eat all types of food, not just their favourite food items.

Question 6.
Did you read the write-up? Analyse it using the indicators given below.
a) Which are the major nutrients?
b) What is the need for preparing food using different ingredients?
c) Why do we eat nutrient rich food?
Answer:
a) Carbohydrates, proteins, fats, vitamins and minerals are the major nutrients.

b) All food items may not contain all essential nutrients in adequate quantity. Hence, we eat a variety of food items prepared using different ingredients.

c) Nutrients are the components required for our growth, to maintain health and to prevent diseases. So we eat nutrient-rich food.

To Obtain Energy
We eat food not only to enjoy the taste, and to satisfy hunger alone. There are many activities in which you usually engage in a day. Observe the picture.

Question 7.
What activities do you see in the picture?
Answer:
Playing with a toy car, playing football, playing with balloons, and reading a book.

Question 8.
Don’t these activities require energy?
Answer:
Yes

Question 9.
Do these activities require the same amount of energy?
Answer:
No, these activities require different amounts of energy.

Let’s examine from where the energy required for these activities is obtained.

Question 10.
What are the food items that should be included more in our diet to get the required amount of energy?
Answer:
Cereals and tubers should be included more in our diet to get the required amount of energy.
Let’s do an experiment to find out if starch is present in the food we eat.

Iodine test
Materials required: Two test tubes, milk, diluted iodine solution, rice water.
Activity – Take two test tubes. Take milk in one test tube and rice water in the other one. Add two or three drops of iodine solution to each test tube. Observe the colour change in both test tubes when iodine solution is added. Repeat the same experiment with other food items you eat.

Question 11.
Record your findings in the table.

Food items	Change in colour when iodine solution is added
Potato	Changes to deep blue colour
Cucumber	No colour change
Maida	Changes to light blue colour
Egg white	No colour change
Milk	No colour change
Curd	No colour change
Tomato Juice	No colour change
Rice water	Changes to deep blue colour
Wheat flour(Atta)	Changes to light blue colour

When iodine combines with starch, a dark blue colour is formed. Depending on the quantity of starch the intensity of blue colour varies.

Question 12.
Find out the food items with more starch content based on the intensity of blue colour formed when iodine was added.
Answer:
Potato and rice water have more starch content as they form a deep blue colour.

Question 13.
You have already listed the food items you usually eat. Analyse the table and examine whether more food items you consume contain starch.
Answer:
Food items like tapioca, wheat flour and rice contain starch.

For Growth
It is not enough to include only carbohydrates in our diet. Let’s find the other nutrients needed for our body.

PROTEIN

Question 14.
Did you notice what the doctor told the child’s mom? Why does the doctor say so?
Answer:
Yes. The child feels tired because he has protein deficiency. Food items like egg, green gram, ground nut, fish, milk etc. are rich in protein. Having them will provide energy.

Read the suggestions given by the dietician in a programme organised by the Health Club in the school.

Question 15.
What are the functions of protein?
Answer:

Question 16.
What are the diseases caused by the deficiency of protein? Discuss.
Answer:
• Kwashiorkor
Kwashiorkor is a condition resulting from inadequate protein intake. The symptoms are fatigue, irritability, growth failure, loss of muscle mass, generalised swelling, protruded belly and decreased immunity.

• Marasmus
The main symptoms of marasmus are extreme thinness, weakness, dry and wrinkled skin, and sunken eyes.
The child may also experience slow growth, lack of body fat, and feel extremely tired all the time.

Question 17.
Pictures of food items which contain protein are given below. Identify them and write.

Answer:
A. Green gram
B. Cashew nut
C. Peanut
D. Egg
E. Milk

Question 18.
Which food items among these are included in your diet?
Answer:
All of them are included in the diet.

Question 19.
There may be vegetarians among you. What food items are to be included in their diet to compensate the deficiency of protein?
Answer:
Green gram, cashew nuts, peanuts, seeds, whole grains, and other pulses are to be included.

Question 20.
Find out more food items which contain protein and write down in the Science Diary.
Answer:
Milk products, fish, meat, soyabean, oats, green peas, asparagus, egg, almonds, pumpkin seeds, walnuts, chickpeas.

Question 21.
Repeat the experiment by rubbing the food items given below on the paper. List them. Discuss your findings in the class.

Answer:

Food items	Observations
Chips	The paper becomes translucent. Fat is present.
Raw banana	Oil patch is not visible. Fat is not present.
Crushed sesame	The paper becomes translucent. Fat is present.
Dried coconut	The paper becomes translucent. Fat is present.
Crushed groundnut	The paper becomes translucent. Fat is present.

Question 22.
Write down the other food items you are familiar with that contain fat.
Answer:
Oil, ghee, meat, egg, coconut, sesame, mustard, ground nut, milk and butter.

We get fat from plant and animal sources.

Question 23.
Observe the pictures given below and write their names. Classify the given pictures as ‘fat obtained from plants’ and ‘fat obtained from animals’.


Answer:

Fat obtained from plants	Fat obtained from animals
A. Coconut oil E. Sunflower oil	C. Fish oil B. Ghee D. Butter

The majority of food items like vegetables, rice, wheat etc1, contain small amount of fat.

Cholesterol
Question 24.
Have you heard doctors advise not to eat too much fatty foods? What could be the reason?
Answer:
Cholesterol is a form of fat. A moderate amount of cholesterol is required for the body. If there is excess cholesterol in the blood, it gets deposited in the inner wall of blood vessels and prevents blood flow. This may cause fatal diseases like stroke and heart failure.

Question 25.
Analyse the table given below to understand different types of vitamins and their significance.

Vitamin	Significance
Vitamin A	Maintains the health of eyes, skin and hair
Vitamin B	Maintains the health of the brain, nerves, heart and skin
Vitamin C	For the health of teeth, gum, blood vessels and for immunity
Vitamin D	For the health of bones and teeth, and for immunity
Vitamin E	For the proper functioning of nerves
Vitamin K	For blood clotting when wounds occur

a) Which vitamins are essential for the health of the skin?
b) What health issues will occur if you don’t get an adequate quantity of vitamin D?
c) Haven’t you analysed the table? Prepare a note on vitamins and present it in the class.
Answer:
a) Vitamin A, Vitamin B

b) Affects the health of bones and teeth. Immunity power decreases.

c) Vitamin is an essential nutrient required for the body. There are different types of vitamins. The function of each of them is different. Vitamin A is essential for eye and hair health. Vitamin A and B are essential for the health of the skin. Vitamin C helps in maintaining the health of teeth, gum and blood vessels and immunity. Vitamin D helps in maintaining the health of bones and teeth. Vitamin E helps in the proper functioning of nerves. Vitamin K is essential for the clotting of blood.

Question 26.
What food items should be included in the diet to prevent the physical issues caused by vitamin deficiency? Observe the table and identify the food items which contain different types of vitamins. Refer to books and elaborate the list by adding more food items.

Answer:

Vitamin	Food items
Vitamin A	Fish, Carrot, Spinach, Cow pea leaf, Colocasia leaf, Moringa leaves, Milk nroducts, liver, Fruits, egg
Vitamin B	Matta rice, Spinach, egg, Colocasia leaf, milk, fish
Vitamin C	Gooseberry, Lemon, moringa leaves. Tomato, guava, papaya, mango, iackfruit, other fruits
Vitamin D	Fish, Egg, cereals, cheese, other milk products
Vitamin E	Peanut, Almond, vegetable oils, egg, milk, ghee, leafy vegetables
Vitamin K	Cabbage, Cauliflower, spinach, milk, egg, fruits

Edible leaves and fruits obtained from our surroundings contain vitamins in abundance. Now we have understood the importance of including food items like moringa leaves, spinach, guava, papaya and mango in our diet.

Water and fat-soluble vitamins

Water-soluble vitamins	Fat-soluble vitamins
Vitamin B, C	Vitamins A, D, E and K In the absence of fat, these vitamins will not be absorbed by the body.

MINERALS

Question 27.
Didn’t you notice the announcement? Why are iron tablets given to children?
Answer:
Iron is a mineral. Such kind of minerals are essential for the proper growth and health of the body. The deficiency of iron can cause many health issues. To avoid such deficiency diseases like anaemia, iron tablets are given to children.

Question 28.
Which are the minerals required for our body? How do these minerals support our growth and health? Analyse the table and write them in the Science Diary.

Important minerals	Food items	Significance
Iron	Leafy vegetables, jaggery, fish, liver	Plays a significant role in the formation of haemoglobin in blood.
Calcium	Egg, milk, leafy vegetables, fish	Helps in the formation of bones, teeth etc. and also helps in the clotting of blood.
Iodine	Sea foods	Helps in the functioning of the thyroid gland.

a) Which mineral helps in the formation of haemoglobin in the blood? What food items should be included in the diet to get this mineral?
b) Why should we eat sea food?
c) What health issues will occur if we avoid eggs, milk and leafy vegetables?
Answer:
a) Iron helps in the formation of haemoglobin in the blood. Leafy vegetables, jaggery, fish, liver etc. should be included in diet to get this mineral.

b) Sea food provides iodine, which helps in the functioning of the thyroid gland.

c) Vitamin C helps in the formation of bones, teeth, etc. and helps in the clotting of blood. Food items like egg, milk and leafy vegetables contain calcium. Avoiding these food items affects the health of teeth, bones and the clotting of blood.

Haemoglobin: Haemoglobin is the pigment present in red blood cells. It imparts red colour to blood. Haemoglobin carries oxygen to the cells and brings back carbon dioxide. A low level of haemoglobin in the blood leads to a condition called anaemia.

Question 29.
You have already learned about the diseases related to protein deficiency. Pay attention to the vitamin deficiency diseases listed below.

a) Deficiency of which vitamin causes scurvy?
b) What food items will you suggest to include in the diet, if someone in your home suffers from mouth ulcer?
c) Deficiency of which vitamin causes night blindness?
d) Deficiency of which vitamin causes rickets?
Answer:
a) Vitamin C
b) Include vitamin B-rich food items like matta rice, spinach, legumes, vegetables, fish, milk, liver, etc., in the diet.
c) Vitamin A
d) Vitamin D

Night Blindness Night blindness is the poor vision experienced in dim light and night. Persons with night blindness have no issues in vision during day time and in bright light at night.

Question 30.
Deficiency diseases caused by the lack of minerals are given in the table below. Analyse the table and find answers to the questions.

Minerals	Deficiency diseases
Iron	Anaemia
Iodine	Goitre
Calcium	Osteoporosis

a) Which disease is caused by the deficiency of iron?
b) What food items should be included in our diet to prevent goitre? Why?
c) What food items are to be included in our diet to prevent osteoporosis?
d) Why are iron tablets supplied in schools? Explain.
e) Analyse the two tables given above. Prepare a write-up on deficiency diseases and display it on the bulletin board.
Answer:
a) Anaemia

b) Sea foods are rich in iodine. They should be included in diet to prevent goitre. It is because goitre is an iodine deficiency disease. So, to prevent goitre, iodine-rich food items are to be included in the diet.

c) Osteoporosis is caused due to the deficiency of calcium. Calcium-rich food items like eggs, milk, fish, leafy vegetables, etc., are to be included in the diet.

d) Iron is a mineral essential for our body. It plays a major role in the formation of haemoglobin in blood. To prevent iron deficiency disease, like anaemia, iron tablets are supplied in schools.

e) Write-up:
• Anaemia is a condition occurring when there is lack of haemoglobin in a person’s blood. Haemoglobin carries oxygen from the lungs to the whole body. The body gets tired quickly when the count of haemoglobin is less. The common symptoms of anaemia are tiredness, paleness and feeling dizzy. This is caused due to the deficiency of Iron. To prevent such a condition, more leafy vegetables, jaggery, fish liver, etc., should be included in the diet.

• Simple goitre is the condition in which the thyroid gland, situated in the throat, becomes enlarged. This is caused by the deficiency of iodine. Iodine is essential to produce hormones by the thyroid gland. To prevent this condition, seafood should be included in the diet.

• Osteoporosis is a condition occurring when bones become soft and brittle, due to the decrease in density of minerals in the bones. This may lead to weakness of bones and fractures. This is caused by the deficiency of calcium. Calcium-rich food items like egg, milk, leafy vegetables, fish, etc. are to be included in the diet.

Question 31.
Which other dietary fibres do you know? Why is it essential to include fibres in the diet? Discuss the note given below. Write down your inferences in the Science Diary.

Fibres Fibres are the cellulose obtained from plant-based food that can’t be digested by our body. Fibres are not nutrient components. However, fibres facilitate the digestion and egestion of faeces through the large intestine. Cereals with bran, leafy vegetables, vegetables, banana stem, banana flower, etc., contain fibres in abundance.

Answer:
Fruits, vegetables, leafy vegetables, banana stem(vazhapindi), vazhakoombu, whole grains, beans, peas, nuts and seeds are rich in fibres.

It is essential to include fibres in the diet because they help in the movement of excretory materials in the large intestine, even though they do not provide any nutrients to the body. They facilitate the digestion and egestion of faeces through the large intestine.

Question 32.
Observe the picture.

Did you see the mango slices and the strained mango juice? Which has more fibre? Why? Discuss.
Answer:
Mango slices have more fibre. Mango slices have the pulp and flesh of the fruit. This part contains
dietary fibre, which helps in digestion and keeps the stomach healthy. Most of the pulp and tiny bits of the fruit are being removed from the strained mango juice. That means most of the fibre is lost when the juice is strained. Therefore, mango slices have more fibre.

So you should try to eat whole fruits like mango, orange and apple instead of their juice.

Water

• About 70% of our body is comprised of water.
• Water is essential for physiological activities like digestion, circulation and excretion.
• Water is lost from the body through urine and sweat. So, we must drink plenty of pure water.
• Children should drink at least 10 to 12 glasses of water a day.
• Vegetables like tomato, cucumber, watermelon, etc., contain plenty of water. So, they are to be included in food.

Question 33.
Earlier, you had prepared the menu for a day. Examine the menu and find out whether it is a balanced diet. If not, make necessary changes in the diet and write them down in the table.

Answer:
Changes to be made in my diet

Items to be included in breakfast	Items to be included in lunch	Items to be included in dinner
Boiled eggs, nuts (For protein) Banana (for fibre), milk (for calcium)	Leafy vegetables (for minerals and vitamins) Fish and meat (For protein)	Roti (for carbohydrates), Ghee (for fat), mixed vegetable salad (for fibres, vitamins and minerals), fruits (for vitamins and fibres).

My Food Plate
We have understood that none of the nutrients discussed so far can be excluded from our diet.

A sample that contains all nutrients is given below. Find out the quantity of food items to be taken in a day from the picture.

Question 34.
Prepare a food chart for a day, including all the nutrients as per your food habit, and exhibit it in your home and class.)

Answer:
An example is given below..

Lunch and its Calorie
Examine the menu of school noon meal for five days.

Question 35.
Which food items are included in it? Discuss the menu of each day with the teacher and examine the food items and the nutrients in them. Tabulate your findings.

Answer:

Question 36.
Did you notice the food items and their nutrients for each day? What did you understand?
Answer:
Yes, we can understand that the menu for the noon meal in schools is prepared to ensure a balanced diet for every child.

Calorie Calorie is the unit that measures the amount of energy in food items. Energy is required for physiological activities like respiration, circulation etc. A man engaged in physical activities requires about 1900 to 2400 calories of energy per day. A woman having physical activities needs about 1600 to 2000 calories of energy per day. A grown-up child needs an average of 1200 to 1400 calories of energy per day.

A child gets about 750 calories of energy from the noon meal. Make it sure to get the remaining amount of calories from the food items you eat at other times.

Question 37.
Can you suggest less expensive and nutritious dishes to improve the noon meal?
Answer:

• Ragi Porridge (Ragi Kanji) using ragi flour, water or milk and jaggery. This dish is rich in calcium, iron and carbohydrates.
• Vegetable pulao and curd salad using different vegetables (beans, carrots, potato, green peas), rice, curd (tomato, onions, cucumber), which is rich in vitamins, minerals, calcium and carbohydrates.
• Rice porridge with green gram curry, raw mango chutney and boiled eggs. This dish is rich in
  carbohydrates, protein, calcium and fibres.
• Also include tubers like tapioca, elephant foot yam (chena), Colocasia (chembu), different types of pulses, banana stem (vazhapindi), vazhakoombu and pickles.

Question 38.
What are your suggestions to get the ingredients for preparing these dishes? Discuss.
Answer:

• A small school vegetable garden which will help grow cultivation habit in children and at the same time it gives the opportunity to have nutritious meals prepared using fresh vegetables, which is economical too.
• Make use of various government schemes that provide support for the noon meal at schools.
• Take help from local societies.
• Take help from various voluntary organisations.

To Prevent Loss of Nutrients
Question 39.
What are the possibilities for the loss of nutrients while cooking? Discuss and write in your Science Diary.
Answer:

• Washing vegetables after cutting them.
• Cooking using a large amount of water.
• Overcooking of vegetables.

Question 40.
Did you understand why it is said that fruits and vegetables should not be washed after cutting them? Discuss with the elders in your home the measures to be adopted to prevent the loss of nutrients from food items. Write them in your Science Diary.
Answer:
Yes.
Measures to be adopted to prevent the loss of nutrients:

• Cook vegetables by covering the vessel
• Don’t overcook vegetables
• The leftover water after cooking vegetables can be used.
• Consume fruits and salads fresh
• Do not peel the vegetables too thick in size.

Now we have understood the need to eat nutritious food for growing up healthy. Nutritious food is not only essential for health, but it is also our right.

Class 6 Basic Science Chapter 1 Question Answer Extended Activities

Question 1.
Prepare the recipe of a food item cooked in your home. Exchange your recipes and read.
Answer:
Avial

Ingredients: Cucumber, Drumstick, Carrot, Yam, Papaya, Tender plantain, ivy gourd (Kovaikka), Pea, Curd, Coconut and green chilli, coconut oil, Curry leaves, Salt and turmeric powder.

Method of Preparation: Cut vegetables into long and narrow slices. Add one teaspoon of turmeric powder and salt for taste. Cook it in a flat vessel. Add scraped coconut and green chilli, which is cut into small pieces, into it. After taking it out from the stove, add curd and stir. Then add coconut oil and curry leaves, stir gentl) and close the vessel.

Question 2.
Prepare a balanced diet chart including items available in your surroundings. Exhibit it in the classroom.
Answer:

	Food items	Nutrients obtained
Breakfast	Breakfast -Puttu and Bengal gram curry, boiled eggs, banana, Wheat bread -butter toast, milk	Carbohydrates (puttu), Protein (boiled eggs, Bengal gram, wheat bread). Fibre (Banana, wheat bread), Fat (wheat bread, butter, toast), calcium (milk)
Lunch	Rice, curd, mixed vegetables, fish curry, gooseberry pickle	Carbohydrates (rice), vitamins and minerals (mixed vegetables), fish curry (protein), curd(calcium), vitamin C (gooseberry pickle)
Tea time	Roasted peanuts, Coconut jaggery laddu	Iron (jaggery), Protein (nuts)
Dinner	Roti, Egg curry, Fruits(Guava ,mango)	Carbohydrates (Roti), protein (Egg curry), Fibres and vitamins (Fruits)

Question 3.
Observe food packets bought from shops and identify the nutrients in them. Prepare a note and present it.
Answer:

Food item	Nutrient chart	Key Nutrients
Toned milk	Nutrient chart • Energy: 62 kcal • Protein: 3.1 g • Fat: 3.0 g • Carbohydrates: 4.8 g • Calcium: 120 mg	• Protein – helps in body repair and growth • Calcium – strengthens bones and teeth • Carbohydrates – provide energy • Fat – Helps in absorbing vitamins
Wheat bread	• Energy: 70-80 kcal • Protein: 2-3 g • Carbohydrates: 13-14 g • Fat: 1-1.5 g • Fibre : 1.5-2 g • Calcium: 25-40 mg • Iron :0.5-1 mg • Sodium: 100-150 mg • Sugar: 1-2 g	• Carbohydrates-Main energy source • Protein – helps in body repair and growth • Fat – Helps in absorbing vitamins • Calcium – For bone and teeth strength • Fibre: Helps in digestion

Question 4.
Conduct a seminar in the class on ‘Food and Health’. Collect information related to different aspects of the topic and prepare a report for presenting in the Seminar.
Answer:
Topic – ‘Food and health’
Introduction: There is a close relationship between food and health. The nutrients our body requires to maintain energy, support growth, prevent sickness, and function correctly are found in the food we eat. Healthy eating practices and a balanced diet are essential for preserving good health.

The main topics for discussion:
1. Importance of food for a healthy body and mind
2. Different food groups and nutrients
3. Deficiency diseases
4. Importance of food hygiene and healthy eating habits

1. Importance of food for a healthy body and mind
Our bodies need the essential nutrients that food gives us in order to survive and lead a healthy life. These nutrients consist of vitamins, minerals, proteins, carbohydrates and fats. Non-nutrient components like water and fibre are also essential. What we eat not only affects our physical health but also our mental health. Healthy food is a must for a healthy mind.

2. Different food groups and nutrients
A healthy diet should include a variety of food groups. Each group provides different nutrients that our body needs. Let’s check the importance of each nutrient factor.

• Carbohydrates -Energy required for the body is mainly obtained from carbohydrates. Carbohydrate is found in food items in different forms like starch, sugar, glucose, cellulose and fibres. Starch is present in abundance in cereals and tubers.
• Proteins: Found in food items like eggs, beans, lentils, meat, and dairy. Protein is essential for
  growth, tissue repair, and immune function.
• Fats -Like carbohydrates and proteins, fat is also essential for us. It helps in absorbing some vitamins. Healthy fats from sources like nuts, olive oil, and avocados help with brain function and hormone production. But it is important to limit unhealthy fats as it can lead to cholesterol and cardiac issues which is a major issue of the time due to the fast food habit and lack of exercise.
• Vitamins and minerals: Fruits and Vegetables are rich in vitamins, minerals, and fibres, they help prevent chronic diseases and improve digestion.
• Calcium: Milk, yogurt, and cheese are rich in calcium and Vitamin D, which are essential for bone and teeth health.

3. Deficiency diseases
Vitamins and minerals are required by the body in small quantities only. However, if they are not available to the body in the required quantity, deficiency diseases are bound to manifest.

• The common vitamin deficiency diseases include night blindness, glossitis, scurvy and rickets.
• The common protein deficiency diseases are kwashiorkor and marasmus.
• Each nutrient is to be taken in a sufficient amount to prevent deficiency diseases. So, including different types of food groups containing the essential nutrients is very important.

4. Importance of food hygiene and healthy eating habits

• In order to maintain health, we should follow a Balanced Diet.
• Drink plenty of water
• Limit junk food habit
• Eat food at proper intervals of time without skipping.
• Control overeating, not just eating ,but eating the required amount with essential nutrients is important.
• Keep food at the correct temperature to avoid bacterial growth.
• Wash hands, utensils, and food before cooking or eating to prevent contamination.
• Ensure food is cooked at the correct temperature to kill harmful bacteria and viruses.
• Always consume food within its shelf life to avoid food poisoning.

Conclusion
A crucial part of preserving health is eating. Our general well-being can be greatly enhanced by following healthy eating practices, eating a well-balanced diet, and paying attention to food safety. We may prevent many diseases and live healthier, happier lives by making educated dietary choices and understanding the connection between food and health.

Food for Health Notes Pdf

Food for Health Class 6 Notes Kerala Syllabus

• Carbohydrates, proteins, fats, vitamins and minerals are the major nutrients.
• Carbohydrates: Energy required for the body is mainly obtained from carbohydrates. Carbohydrate is found in food items in different forms like starch, sugar, glucose, cellulose and fibres.
• Iodine test is done to find if starch is present in the food we eat. When iodine combines with starch in a food item dark blue colour is formed.
• Protein: Protein is a nutrient essential for growth and body building. Protein is required for the health of muscles, hair and skin. Moreover, proteins provide energy. The deficiency of protein causes diseases like Kwashiorkor and Marasmus.
• Fats are essential because they help in the absorption of vitamins like A, D, E, and K, which are soluble only in fat.
• Vitamins are essential nutrients required in small quantities for the growth and health of our body. They are essential for health of eyes, hair, skin, brain, bones, nerves, heart, teeth, gum and blood vessels. They also help in maintaining immunity, helps in the proper functioning of nerves and is essential for clotting of blood.
• The pigment haemoglobin present in red blood cells imparts red colour to blood and it carries oxygen to the cells and bring back carbon dioxide. Low level of haemoglobin in the blood leads to a condition called anaemia.
• Minerals like iron, calcium, iodine are essential in the formation of haemoglobin in blood, formation of bones, teeth and clotting of blood, and help in the functioning of the thyroid gland.
• Night blindness, Glossitis, Mouth Ulcer, bleeding gums (Scurvy) and rickets are the vitamin deficiency diseases.
• Anaemia is caused due to deficiency of iron
• Goitre is caused to deficiency of iodine.
• Osteoporosis is caused due to deficiency of calcium.
• Fibres and water are non-nutrient components.
• Fibres are the cellulose obtained from plant-based food that can’t be digested by our body. Fibres facilitate digestion and egestion of faeces through the large intestine.
• Water is essential for physiological activities like digestion, circulation and excretion.
• In order to maintain health, we should follow a diet that includes protein, carbohydrate, fat, vitamins and minerals in appropriate quantities. Such a diet is called a Balanced Diet.
• Fruits and vegetables should not be washed after cutting them and vegetables should be cooked by covering the vessel to prevent loss of nutrients in them.

INTRODUCTION

Eating a variety of healthy foods like fruits, vegetables, nuts, cereals, meat, fish, eggs, and pulses helps to keep our body strong and healthy. Our body needs nutrients like carbohydrates, proteins, vitamins, minerals, and fats to grow and stay active. Food gives us the energy to do work and helps our brain and body function properly. Eating a healthy diet can improve sleep, boost energy, and protect us from illness. A balanced diet helps us feel good and live a healthy life. In this chapter, we deal with topics like food and nutrients, deficiency diseases, components other than nutrients and balanced diet.

FOOD AND NUTRIENTS
Why Food?
Understand why do we eat food and what do we get from food by reading the write-up from a children’s magazine.

Our Health: Food provides energy for our daily physiological activities. Nutrients are the components required for our growth, to maintain health and to prevent diseases. We obtain nutrients from food items. Carbohydrates, proteins, fats, vitamins and minerals are the nutrients present in food items. Though water is not a nutrient component, it is an important requirement for our bodily activities. Fibres present in the food items are also required for bodily activities. All food items may not contain all essential nutrients in adequate quantity. Hence, we eat a variety of food items prepared using different ingredients. The quantity of food we eat, its quality and time of consumption influence our health. So, everyone should eat nutritious food.

CARBOHYDRATE

FAT

Like carbohydrate and protein, fat is also essential for us. If we consume equal amount of carbohydrate, protein and fat, we will get more energy from fat.

Activity to find out the presence of fat in your diet
Take a sheet of paper and put a drop of oil on it. Observe the paper. Likewise put a drop of ghee on another piece of paper. Identify the presence of fat by observing the changes in the paper when ghee and oil were added.

VITAMINS

Vitamins are essential nutrients required in small quantities for the growth and health of our body.

Let’s understand the importance of vitamins.

DEFICIENCY DISEASES
Deficiency Diseases
Vitamins and minerals are required by the body in small quantities only. However, if they are not available to the body in the required quantity, deficiency diseases are bound to manifest.

COMPONENTS OTHER THAN NUTRIENTS
Components other than Nutrients
Just like nutrients, there are certain other components that are required for our health. Let’s see what they are. Cut a banana stem and observe the fibres in it.

BALANCED DIET

Balanced Diet In order to maintain health, we should follow a diet that includes protein, carbohydrate, fat, vitamins and minerals in appropriate quantities. Such a diet is called a Balanced Diet.

There is no single food item we discussed earlier that contains all the nutrients in adequate quantities. We compensate the nutrient deficiency in one food item with another one. So the food we eat should be diverse.

Expert Teachers at HSSLive.Guru has created Class 6 Malayalam Kerala Padavali Notes Pdf Free Download of 6th Standard Malayalam Kerala Padavali Textbook Solutions Questions and Answers Notes Pdf Chapters Summary in Malayalam, കേരള പാഠാവലി 6 Notes are part of Kerala Syllabus 6th Standard Textbooks Solutions. Here we have given Std 6 Malayalam Kerala Padavali Notes Pdf Free Download of SCERT Class 6 Malayalam Kerala Padavali Solutions Part 1 and Part 2. Students can also read Class 6 Malayalam Adisthana Padavali Notes Pdf.

Class 6 Malayalam Kerala Padavali Question Answer Pdf Download

Kerala Padavali Malayalam Standard 6 Notes Pdf

6th Standard Malayalam Kerala Padavali Notes Part 1

Unit 1 അമൃതം നുകരാം

• Chapter 1 അടുക്കള Notes – Adukkala Question Answer
• Chapter 2 ചട്ടിപ്പത്തിരി Notes – Chatti Pathiri Question Answer
• Chapter 3 കൊയക്കട്ട Notes – Koyakkatta Question Answer
• Chapter 4 കായെല്ലമു നെവേഞ്ചിമു തന്തിനു ചവി Notes – Kayellamu Nevenjimu Thanthintha Chavi Question Answer

Unit 2 നടുകിൽ തിന്നാം

• Chapter 5 കോയയുടെ ചെറിയ വസ്തുക്കൾ Notes – Koyayude Cheriya Vasthukkal Question Answer
• Chapter 6 ഗാന്ധിജിയുടെ അതിഥി Notes – Gandhijiyude Athidhi Question Answer
• Chapter 7 തൊഴിലിന്റെ രുചി, ഭാഷയുടെയും Notes – Thozhilinte Ruchi, Bhashayudeyum Question Answer

Unit 3 നൽകുകിൽ നേടാം

• Chapter 8 വയൽക്കാഴ്ചകൾ Notes – Vayalkkaazhchakal Question Answer
• Chapter 9 അതിജീവനത്തിന്റെ തുടക്കം Notes – Adhijeevanathinte Thudakkam Question Answer
• Chapter 10 ഒരു സ്വപ്നമുണ്ടായിരുന്നു Notes – Oru Swapnamundayirunnu Question Answer

Kerala Padavali Class 6 Notes Part 2

Unit 4 അറിഞ്ഞു വിടരാം

• Chapter 11 ശാസ്ത്രം മുന്നേറുന്നു Notes – Shastram Munnerunnu Question Answer
• Chapter 12 ആദ്യത്തെ പറക്കൽ Notes – Aadyathe Parakkal Question Answer
• Chapter 13 പന്തങ്ങൾ Notes – Panthangal Question Answer

Unit 5 ഉണർന്നുയരാം

• Chapter 14 ചെമ്പകപ്പൂവ് Notes – Chempakapoovu Question Answer
• Chapter 15 ആദ്യപാഠങ്ങൾ Notes – Aadyapaadangal Question Answer
• Chapter 16 ഗോട്ടി Notes – Gotti Question Answer

Class 6 Kerala Padavali Notes Chapters Summary

• Chapter 1 Adukkala Summary
• Chapter 2 Chatti Pathiri Summary
• Chapter 3 Koyakkatta Summary
• Chapter 4 Kayellamu Nevenjimu Thanthintha Chavi Summary
• Chapter 5 Koyayude Cheriya Vasthukkal Summary
• Chapter 6 Gandhijiyude Athidhi Summary
• Chapter 7 Thozhilinte Ruchi, Bhashayudeyum Summary
• Chapter 8 Vayalkkaazhchakal Summary
• Chapter 9 Adhijeevanathinte Thudakkam Summary
• Chapter 10 Oru Swapnamundayirunnu Summary
• Chapter 11 Shastram Munnerunnu Summary
• Chapter 12 Aadyathe Parakkal Summary
• Chapter 13 Panthangal Summary
• Chapter 14 Chempakapoovu Summary
• Chapter 15 Aadyapaadangal Summary
• Chapter 16 Gotti Summary

SCERT Class 6 Malayalam Kerala Padavali Solutions (Old Syllabus)

Unit 1 ചിത്രവർണങ്ങൾ

• Chapter 1 ഒരു ചിത്രം Notes – Oru Chithram Question Answer
• Chapter 2 ഓടയിൽനിന്ന് Notes – Odayil Ninnu Question Answer
• Chapter 3 മയന്റെ മായാജാലം Notes – Mayante Mayajalam Question Answer

Unit 2 കലയുടെ കേദാരം

• Chapter 4 പാട്ടിന്റെ പാലാഴി Notes – Pattinte Palazhi Question Answer
• Chapter 5 ജീവനുള്ള പാട്ട് Notes – Jeevanulla Pattu Question Answer
• Chapter 6 പടയണി Notes – Padayani Question Answer

Unit 3 മായക്കാഴ്ചകൾ

• Chapter 7 ഹാമെലിനിലെ കുഴലൂത്തുകാരൻ Notes – Hamelinile Kuzhaloothukaran Question Answer
• Chapter 8 ചിത്രശലഭങ്ങൾ Notes – Chithrashalabhangal Question Answer

Unit 4 പ്രകാശകിരണങ്ങൾ

• Chapter 9 പരിശ്രമം ചെയ്യുകിലെന്തിനേയും Notes – Parisramam Cheyyukil Enthineyum Question Answer
• Chapter 10 മഞ്ഞുതുള്ളി Notes – Manjuthulli Question Answer
• Chapter 11 ഒരു കെട്ടുകല്യാണം Notes – Oru Kettu Kalyanam Question Answer

Unit 5 പ്രകൃതിഭാവങ്ങൾ

• Chapter 12 വിക്ടോറിയാ വെള്ളച്ചാട്ടം Notes – Victoria Vellachattam Question Answer
• Chapter 13 സാധ്യമെന്ത് Notes – Sadhyamenthu Question Answer
• Chapter 14 പുഴ Notes – Puzha Question Answer

Class 6 Kerala Padavali Notes Chapters Summary (Old Syllabus)

• Chapter 1 Oru Chithram Summary
• Chapter 2 Odayil Ninnu Summary
• Chapter 3 Mayante Mayajalam Summary
• Chapter 4 Pattinte Palazhi Summary
• Chapter 5 Jeevanulla Pattu Summary
• Chapter 6 Padayani Summary
• Chapter 7 Hamelinile Kuzhaloothukaran Summary
• Chapter 8 Chithrashalabhangal Summary
• Chapter 9 Parisramam Cheyyukil Enthineyum Summary
• Chapter 10 Manjuthulli Summary
• Chapter 11 Oru Kettu Kalyanam Summary
• Chapter 12 Victoria Vellachattam Summary
• Chapter 13 Sadhyamenthu Summary
• Chapter 14 Puzha Summary

Class 6 Malayalam Kerala Padavali Question Paper Pdf (Old Syllabus)

• Class 6 Malayalam Kerala Padavali Annual Exam Question Paper 2023-24
• Class 6 Malayalam Kerala Padavali First Term Question Paper 2022-23
• Class 6 Malayalam Kerala Padavali Second Term Question Paper 2022-23
• Class 6 Malayalam Kerala Padavali Annual Exam Question Paper 2022-23
• Std 6 Malayalam Kerala Padavali Annual Exam Question Paper 2021-22

We hope the given Kerala Syllabus 6th Standard Malayalam Kerala Padavali Notes, Class 6 Malayalam Kerala Padavali Question Answer will help you. If you have any queries regarding Kerala Padavali Malayalam Standard 6 Notes Guide Pdf, Class 6 Kerala Padavali Notes drop a comment below and we will get back to you at the earliest.

The comprehensive approach in 10th Class Physics Notes Malayalam Medium and Class 10 Physics Chapter 3 Important Questions Malayalam Medium കാഴ്ചയും വർണ്ണങ്ങളുടെ ലോകവും ensure conceptual clarity.

SSLC Physics Chapter 3 Important Questions Malayalam Medium

കാഴ്ചയും വർണ്ണങ്ങളുടെ ലോകവും Class 10 Important Questions

Question 1.
കൂട്ടത്തിൽ പെടാത്തത് കണ്ടെത്തി എഴുതുക.
a) ചുവപ്പ്, പച്ച, മജന്ത, നീല
b) മജന്ത, മഞ്ഞ, സയൻ, പച്ച
Answer:
a) മജന്ത
b) പച്ച

Question 2.
ചുവപ്പ്, പച്ച, നീല എന്നീ വർണ്ണങ്ങളെ …………………. എന്ന് വിളിക്കുന്നു.
Answer:
പ്രാഥമിക വർണ്ണങ്ങൾ

Question 3.
ഏതെങ്കിലും രണ്ടു പ്രാഥമിക വർണ്ണപ്രകാശങ്ങൾ ചേർന്നുണ്ടാകുന്ന വർണ്ണപ്രകാശമാണ്…………………….
Answer:
ദ്വിതീയ വർണ്ണം

Question 4.
പൂരകവർണ്ണങ്ങൾ എന്നാൽ എന്ത്?
Answer:
ഒരു ദ്വിതീയ വർണ്ണത്തോടു കൂടി ഏതു വർണ്ണം ചേരുമ്പോഴാണോ ധവളപ്രകാശം ലഭിക്കുന്നത് ആ വർണ്ണജോഡികളാണ് പൂരകവർണ്ണങ്ങൾ

Question 5.
ചുവടെ നൽകിയ പ്രസ്താവനകളിൽ ശരിയായത് ഏത്?
a) എല്ലാ വർണ്ണങ്ങളെയും പ്രതിപതിപ്പിക്കുന്ന പ്രതലം ധവള പ്രകാശത്തിൽ ഇരുണ്ട നിറത്തിൽ കാണപ്പെടും.
b) എല്ലാ വർണ്ണങ്ങളെയും ആഗിരണം ചെയ്യുന്ന പ്രതലം വെളുത്ത നിറത്തിൽ കാണപ്പെടും.
c) എല്ലാ വർണ്ണങ്ങളെയും പ്രതിപതിപ്പിക്കുന്ന പ്രതലം ധവള പ്രകാശത്തിൽ വെളുത്ത നിറത്തിൽ കാണപ്പെടും.
Answer:
c) എല്ലാ വർണ്ണങ്ങളെയും പ്രതിപതിപ്പിക്കുന്ന പ്രതലം ധവള പ്രകാശത്തിൽ വെളുത്ത നിറത്തിൽ കാണപ്പെടും.

Question 6.
കാരണം കണ്ടെത്തുക.
a) ഒരു സസ്പെൻഷനിലൂടെ പ്രകാശം കടന്നു പോകുമ്പോഴുള്ള പ്രകാശപാത വ്യക്തമായി കാണാൻ
കഴിയുന്നു.
b) ആകാശം നീലനിറത്തിൽ കാണുന്നു.
c) ഉദയാസ്തമയ സമയങ്ങളിൽ സൂര്യന്റെ നിറം ചുവപ്പോ, മഞ്ഞയോ, ഓറഞ്ചോ ആയി കാണുന്നു.
Answer:
a) വിസരണം

b) സൂര്യപ്രകാശം അന്തരീക്ഷവായുവിലൂടെ സഞ്ചരിച്ചാണ് ഭൂമിയിലെത്തുന്നത്. അപ്പോൾ പ്രകാശത്തിന്റെ ഒരു ഭാഗം വിസരണത്തിന് വിധേയമാകുന്നു. വിസരണം ഏറ്റവും കൂടുതൽ സംഭവിക്കുന്നത് തരംഗദൈർഘ്യം കുറഞ്ഞ വർണ്ണങ്ങളായ വയലറ്റ്, ഇൻഡിഗോ, നീല എന്നിവയ്ക്ക് ആയിരിക്കും. ഈ വിസരിത പ്രകാശമാണ് ആകാശത്ത് വ്യാപിക്കുന്നത്. നിരീക്ഷകന്റെ കണ്ണിലെത്തുന്ന പരിണത വിസരിത പ്രകാശം നീല വർണ്ണത്തിന്റെ ഫലം നൽകുന്നതു കൊണ്ട് ആകാശം നീലനിറത്തിൽ കാണുന്നു.

c) ഉദയാസ്തമയ സമയങ്ങളിൽ സൂര്യരശ്മിക്ക് നിരീക്ഷകന്റെ കണ്ണുകളിലെത്താൻ അന്തരീക്ഷത്തിലൂടെ സഞ്ചരിക്കേണ്ട ദൂരം മറ്റു സമയത്തെ അപേക്ഷിച്ച് കൂടുതൽ ആയിരിക്കും. ഈ സമയങ്ങളിൽ ഏറ്റവും കുറവ് വിസരണം സംഭവിക്കുന്നത് തരംഗദൈർഘ്യം കൂടിയ ചുവപ്പ്, മഞ്ഞ, ഓറഞ്ച് എന്നീ വർണ്ണങ്ങൾ ക്കായിരിക്കും.

Question 7.
ചേരുംപടി ചേർക്കുക

A	B
നിയർ പോയിന്റ്	കോൺകേവ് ലെൻസ്
ഫാർ പോയിന്റ്	25 cm
ഹ്രസ്വദൃഷ്ടി	കോൺവെക്സ് ലെൻസ്
ദീർഘദൃഷ്ടി	അനന്തത

Answer:

A	B
നിയർ പോയിന്റ്	25 cm
ഫാർ പോയിന്റ്	അനന്തത
ഹ്രസ്വദൃഷ്ടി	കോൺകേവ് ലെൻസ്
ദീർഘദൃഷ്ടി	കോൺവെക്സ് ലെൻസ്

Question 8.
പട്ടിക പൂർത്തീകരിക്കൂ.

ദ്വിതീയ വർണ്ണം	പൂരകവർണ്ണം
മഞ്ഞ	……………(a) ……………
………….(b)…………..	പച്ച
സയൻ	……………(c) ……………

Answer:
a) നീല
b) മജന്ത
c) ചുവപ്പ്

Question 9.
ഒരു വൃത്തത്തകിടിന്റെ പകുതി ഭാഗത്ത് ക്രയോൺ ഉപയോഗിച്ച് ഇളം മജന്ത നിറവും മറുപകുതിയിൽ ഇളം പച്ച നിറവും നൽകൂ. ഈ വൃത്തത്തകിടിനെ അതിവേഗം കറക്കി നോക്കൂ. എന്ത് നിരീക്ഷിക്കുന്നു? കാരണമെന്ത്?
Answer:
വൃത്തത്തകിട് വെളുത്ത നിറത്തിൽ കാണുന്നു. കണ്ണിന്റെ വീക്ഷണസ്ഥിരത എന്ന പ്രത്യേകത മൂലമാണ് ഇത് സംഭവിക്കുന്നത്. പൂരകവർണ്ണജോഡികൾ ചേരുമ്പോൾ ധവളപ്രകാശം ലഭിക്കുന്നു.

Question 10.
പട്ടിക പൂർത്തീകരിക്കൂ.

ഫിൽറ്റർ	ഫിൽറ്ററിൽ പതിക്കുന്ന പ്രകാശം	കടത്തിവിടുന്നു / കടത്തി വിടുന്നില്ല
മഞ്ഞ	ചുവപ്പ്
	പച്ച
	നീല
	മജന്ത
	ധവളം

Answer:

ഫിൽറ്റർ	ഫിൽറ്ററിൽ പതിക്കുന്ന പ്രകാശം	കടത്തിവിടുന്നു / കടത്തി വിടുന്നില്ല
മഞ്ഞ	ചുവപ്പ്	ചുവപ്പിനെ കടത്തിവിടുന്നു
	പച്ച	പച്ചയെ കടത്തിവിടുന്നു
	നീല	നീലയെ കടത്തിവിടുന്നില്ല
	മജന്ത	ചുവപ്പിനെ കടത്തിവിടുന്നു
	ധവളം	ചുവപ്പ്, നീല, മഞ്ഞ എന്നിവയെ കടത്തിവിടുന്ന

Question 11.
ഒന്നാം പദജോഡി ബന്ധം കണ്ടെത്തി രണ്ടാമത്തെ പദജോഡി പൂർത്തിയാക്കുക.
നീല : പ്രാഥമിക വർണ്ണം
സയൻ : …………………
Answer:
ദ്വിതീയവർണ്ണം

Question 12.
സൂര്യരശ്മികളിലെ താപത്തിന് കാരണം വികിരണങ്ങളാണ്.
Answer:
ഇൻഫ്രാറെഡ്

Question 13.
വ്യത്യസ്ത വർണ്ണങ്ങൾ ചേർന്നുണ്ടാകുന്ന പ്രകാശമാണ്..
Answer:
സമന്വിത പ്രകാശം

Question 14.
ഒരു സമന്വിത പ്രകാശം ഘടക വർണ്ണങ്ങളായി വേർപിരിയുന്ന പ്രതിഭാസമാണ്………………….
Answer:
പ്രകീർണ്ണനം

Question 15.
പട്ടിക പൂർത്തീകരിക്കൂ.

ഫിൽറ്റർ –	ഫിൽറ്ററിൽ പതിക്കുന്ന പ്രകാശം	കടത്തിവിടുന്നു / കടത്തി വിടുന്നില്ല
സയൻ	ചുവപ്പ്
	പച്ച
	നീല-
	മജന്ത
	ധവളം

Answer:

ഫിൽറ്റർ –	ഫിൽറ്ററിൽ പതിക്കുന്ന പ്രകാശം	കടത്തിവിടുന്നു കടത്തി വിടുന്നില്ല.
സയൻ	ചുവപ്പ്	ചുവപ്പിനെ കടത്തിവിടുന്നില്ല
	പച്ച	പച്ചയെ കടത്തിവിടുന്നു
	നീല-	നീലയെ കടത്തിവിടുന്നു
	മജന്ത	നീലയെ കടത്തിവിടുന്നു
	ധവളം	പച്ച, നീല എന്നിവയെ കടത്തിവിടുന്നു

Question 16.
കണ്ണിലെ പ്രതിബിംബ രൂപീകരണവുമായി ബന്ധപ്പെട്ട് താഴെ കൊടുത്ത ചിത്രം നിരീക്ഷിക്കുക.

(a) ഹ്രസ്വദൃഷ്ടിയുള്ള കണ്ണിനെ സൂചിപ്പിക്കുന്ന ചിത്രം ഏത്?
(b) ഈ ന്യൂനതയ്ക്കുള്ള കാരണങ്ങൾ എന്തെല്ലാം?
(c) ഇത് പരിഹരിക്കുന്നതെങ്ങനെ?
Answer:
a. B
b.
i. നേത്രഗോളത്തിന്റെ വലിപ്പക്കൂടുതൽ
ii. തലെൻസിന് ഫോക്കസ് ദൂരം കുറവ് (അഥവാ പവർ കൂടുതൽ)
c. അനുയോജ്യമായ പവറുള്ള കോൺകേവ് ലെൻസുപയോഗിക്കുക

Question 17.
സൂര്യ രശ്മികൾ ഒരു ഗ്ലാസ് പ്രിസത്തിലേക്ക് പ്രവേ ശിക്കുന്നതാണ് ചിത്രത്തിൽ കൊടുത്തിരിക്കുന്നത്

ചിത്രം പകർത്തി പ്രകാശം സ്ക്രീനിൽ പതിക്കുന്നത് ചിത്രീകരിച്ച് വർണ്ണങ്ങൾ അടയാളപ്പെടുത്തുക.
Answer:

വയലറ്റ്, ഇന്റിഗോ, നീല, പച്ച, മഞ്ഞ, ഓറഞ്ച്, ചുവപ്പ് എന്നീ നിറങ്ങൾ മുകളിൽ കാണിച്ചിരിക്കുന്ന ക്രമത്തിൽ പതിക്കും.

Question 18.
ഒരു വസ്തുവിനെ വ്യക്തമായി കാണാൻ കഴിയുന്ന ഏറ്റവും അടുത്തുള്ള ബിന്ദു ഏത് പേരിൽ അറിയ പ്പെടുന്നു?
Answer:
നിയർ പോയിന്റ്

Question 19.
അടുത്തുള്ള വസ്തു വിനെ നോക്കുമ്പോൾ കണ്ണിലെ ലെൻസിന്റെ വക്രത ………………… (കൂടുന്നു /
കുറയുന്നു)
Answer:
കൂടുന്നു

Question 20.
ബന്ധം കണ്ടെത്തി പൂരിപ്പിക്കുക.
ദീർഘദൃഷ്ടി : കോൺവെക്സ് ലെൻസ്
വെള്ളെഴുത്ത് : ………………….
Answer:
കോൺവെക്സ് ലെൻസ്

Question 21.
മഴവില്ലിന്റെ പുറം വക്കിൽ കാണപ്പെടുന്ന നിറംഏത്?
Answer:
ചുവപ്പ്

Question 22.
വീക്ഷണസ്ഥിരത മൂലം ഒരു ദൃശ്യം റെറ്റിനയിൽ തങ്ങി നിൽക്കുന്ന സമയം എത്
(1/10 s, 1/12 s, 1/16 s, 1/20 s)
Answer:
1/16 s

Question 23.
സമഞ്ജനക്ഷമത എന്നാൽ എന്ത്?
Answer:
വസ്തുക്കളുടെ സ്ഥാനം എവിടെയായിരുന്നാലും പ്രതിബിംബം റെറ്റിനയിൽ പതിക്കത്തക്കവിധം ലെൻസിന്റെ വക്രത വ്യത്യാസപ്പെടുത്തി ഫോക്കസ് ദൂരം ക്രമീകരിക്കാനുള്ള കഴിവാണ് കണ്ണിന്റെ സമ ജനക്ഷമത.

Question 24.
മഴവില്ലിന്റെ രൂപീകരണ സമയത്ത് പ്രകാശത്തിന് ഒരു ജലകണികളിൽ സംഭവിക്കുന്ന പ്രകീർണന ത്തിന്റെ ചിത്രം വരയ്ക്കുക?

Question 25.
പ്രകാശ മലിനീകരണം കൊണ്ടുള്ള ഏതെങ്കിലും രണ്ട് അനന്തരഫലങ്ങൾ എഴുതുക?
Answer:
ജീവജാലങ്ങളുടെ സ്വാഭാവിക ജീവിതക്രമത്തെ പ്രതി കൂലമായി ബാധിക്കുന്നു. ആകാശക്കാഴ്ച മറയ്ക്ക ന്നത് മൂലം വാനനിരീക്ഷണം അസാധ്യമാകുന്നു.

Question 26.
വാഹനങ്ങളുടെ ടെയിൽ ലാമ്പുകൾക്കും സിഗ്നൽ ലാമ്പുകൾക്കും ചുവപ്പുനിറം നൽകിയത് എന്തിന്?
Answer:
തരംഗദൈർഘ്യം കൂടുതലുള്ള ചുവപ്പു വർണ ത്തിനു വിസരണം കുറവാണ്. അതിനാൽ വളരെ ദൂരം നിന്നും ശ്രദ്ധ കിട്ടാൻ സഹായിക്കും.

Question 27.
ന്യൂട്ടന്റെ വർണ്ണപമ്പരം വേഗത്തിൽ കറക്കുമ്പോൾ ഏത് നിറത്തിൽ കാണപ്പെടുന്നു? എന്തുകൊണ്ട്?
Answer:
ഉയർന്ന വേഗതയിൽ സഞ്ചരിക്കുമ്പോൾ മനു ഷ്യന്റെ കണ്ണുകൾക്ക് വ്യത്യസ്ത നിറങ്ങൾ തമ്മിൽ വേർതിരിച്ചറിയാൻ കഴിയില്ല. വെളുത്തപ്രകാശം ഏഴ് നിറങ്ങൾ ഉൾക്കൊള്ളുന്നു. അതിനാൽ, ഏഴ് നിറ ങ്ങളുള്ള ഒരു ന്യൂട്ടന്റെ കളർ ഡിസ്ക് ഉയർന്ന വേഗ തയിൽ തിരിക്കുമ്പോൾ, നിറങ്ങൾ ചേർന്ന് ഡിസ്ക് വെള്ളയായി ദൃശ്യമാകുന്നു.

Question 28.
ഒരാളുടെ കണ്ണിലെ പ്രതിബിംബ രൂപീകരണത്തിന്റെ ചിത്രം നൽകിയിരിക്കുന്നു.

a) അയാളുടെ നേതവൈകല്യം എന്ത്?
b) കണ്ണിന്റെ ഈ ന്യൂനതയ്ക്ക് കാരണമെന്ത്?
c) ഈ ന്യൂനത പരിഹരിക്കാൻ ഏതുതരം ലെൻസ് ആണ് ഉപയോഗിക്കേണ്ടത്?
Answer:
a) ഹൃസ്വദൃഷ്ടി

b) നേത്രഗോളത്തിന്റെ വലിപ്പം കൂടുന്നു.
ലെൻസിന്റെ പവർ കൂടുന്നു.

c) കോൺകേവ് ലെൻസ്

Question 29.
സമന്വിത പ്രകാശം ഘടകവർണ്ണങ്ങളായി വേർതി രിക്കുന്ന ചിത്രം നൽകിയിരിക്കുന്നു.

a) ഇതിന് കാരണമായ പ്രതിഭാസത്തിന്റെ പേരെന്ത്?
b) വർണ്ണങ്ങളുടെ ദിശാവ്യതിയാനം വ്യത്യസ്ത മാവാൻ എന്താണ് കാരണം?
c) ഇത്തരത്തിൽ വേർപിരിഞ്ഞ ധവള പ്രകാശ ത്തിലെ ഘടകവർണ്ണങ്ങളെ എങ്ങനെ പുന സംയോജിപ്പിക്കാം? ചിത്രത്തിന്റെ സഹായ ത്തോടെ വിശദീകരിക്കുക?
Answer:
a) പ്രകീർത്തനം

b) വർണ്ണങ്ങളുടെ തരംഗദൈർഘ്യം വ്യത്യസ്ത മായതിനാൽ ദിശാവ്യതിയാനവും വ്യത്യസ്ത മായിരിക്കും.

c) പ്രിസത്തിലൂടെ ധവളപ്രകാശം കടത്തിവിട്ട് ഘട കവർണ്ണങ്ങൾ സ്ക്രീനിൽ പതിപ്പിക്കുന്നു. സമാ നമായ മറ്റൊരു പിസമെടുത്ത് പാദം മുകളിൽ വരത്തക്ക വിധം ചിത്രത്തിലേതു പോലെ ആദ്യത്തെ പ്രിസത്തോട് ചേർത്ത് വച്ചാൽ ധവ പ്രകാശം ലഭിക്കും.

Question 30.
പ്രകൃതിയുടെ ഒരു മിഴിവാർന്ന ദൃശ്യാനുഭവം ആണ് മഴവില്ല്. മഴവില്ല് രൂപപ്പെടുന്നത് എങ്ങനെ?
Answer:
സൂര്യപ്രകാശം ജലകണികകളിലൂടെ കടന്നുപോ കുമ്പോൾ അപവർത്തനത്തിനും ആന്തര പ്രതിഫ ലനത്തിനും വിധേയമാകുന്നു. ദൃഷ്ടി രേഖയുമായി ഒരേ കോർണറിൽ കാണപ്പെടുന്ന കണികകളിലൂടെ പുറത്തുവരുന്ന പ്രകാശരശ്മി ഒരേ വർണ്ണത്തിൽ ഉള്ളവ ആയതിനാൽ ഇവ ഒരു വൃത്ത പാദത്തിൽ സ്ഥിതി ചെയ്യുന്നതായി നമുക്ക് അനുഭവപ്പെടുന്നു അപ്രകാരം പുറം വക്കിൽ ചുവപ്പും അകവശത്ത് വയലറ്റും മറ്റു വർണ്ണങ്ങൾ തരംഗ ദൈർഘ്യത്തിന് അനുസരിച്ച് ഇവയ്ക്കിടയിലായും കാണപ്പെടുന്നു. ഇത്തരത്തിലാണ് മഴവില്ല് ഉണ്ടാകുന്നത്.

Question 31.
വേഗത്തിൽ ചുഴറ്റുന്ന തീപ്പന്തത്തിന്റെ പാത വൃത്താ കൃതിയിൽ കാണപ്പെടുന്നു.
a) ഇതിന് കാരണം എന്ത്?
b) ഇതിനു സമാനമായ മറ്റു രണ്ടു ഉദാഹരണങ്ങൾ എഴുതുക?
Answer:
a) വീക്ഷണസ്ഥിരത മൂലം

b) മഴപെയ്യുമ്പോൾ താഴേക്ക് പതിക്കുന്ന മഴത്തു ള്ളികൾ സ്ഫടിക ദണ്ഡ് പോലെ കാണപ്പെടു ന്നു. ന്യൂട്ടന്റെ വർണ്ണ പമ്പരം വേഗത്തിൽ കറ ക്കുമ്പോൾ വെള്ളയായി കാണപ്പെടുന്നു.

Question 32.
പ്രകാശം നേർരേഖയിലാണ് സഞ്ചരിക്കുന്നതെ ങ്കിലും വീടിനുള്ളിൽ പകൽ സമയത്ത് പ്രകാശം ലഭിക്കാറുണ്ട്.
a) ഇതിന് കാരണം എന്ത്?
b) പകൽ സമയത്ത് ആകാശം നീലനിറത്തിൽ കാണാനുള്ള കാരണം വ്യക്തമാക്കുക?
Answer:
a) പ്രകാശത്തിനു മാധ്യമത്തിലെ കണങ്ങളിൽ തട്ടി സംഭവിക്കുന്ന ക്രമരഹിതവും ഭാഗികവുമായ ദിശ വ്യതിയാനമാണ് വിസരണം.

b) സൂര്യപ്രകാശത്തിലെ തരംഗദൈർഘ്യം
കുറഞ്ഞ വയലറ്റ്, ഇൻഡിഗോ, നീല എന്നീ * വർണ്ണങ്ങൾ അന്തരീക്ഷത്തിലെ കണങ്ങളിൽ തട്ടി കൂടുതൽ വിസരണത്തിനു വിധേയമാകു ന്നതിനാൽ ആകാശം നീലനിറത്തിൽ കാണപ്പെ ടുന്നു.

Question 33.
കാഴ്ച എന്ന അനുഭവം സാധ്യമാക്കുന്നതിൽ മുഖ്യ പങ്ക് വഹിക്കുന്നത് നമ്മുടെ കണ്ണുകളാണ്.
a) വസ്തുവിന്റെ സ്ഥാനം മാറുന്നതിനനുസരിച്ച് പ്രതിബിംബം റെറ്റിനയിൽ പതിക്കാൻ സഹാ യിക്കുന്ന കണ്ണിന്റെ ഭാഗം ഏത്?
b) കണ്ണിൽ നിന്ന് 10 cm അകലെ പിടിച്ചിരിക്കുന്ന ഒരു ദിനപത്രത്തിലെ വരികൾ വ്യക്തമായി കാണാൻ സാധിക്കുന്നില്ല. എന്തായിരിക്കാം കാരണം?
c) കാഴ്ചയ്ക്ക് ബുദ്ധിമുട്ടുള്ള ഒരാൾക്ക് കണ്ണട യ്ക്കായി ഡോക്ടർ നല്കിയ കുറിപ്പിൽ -2D എന്ന് രേപ്പെടുത്തിയിരിക്കുന്നു. എങ്കിൽ ഏതു തരം ലെൻസ് ആണ് കുറിപ്പിൽ സൂചിപ്പിച്ചിട്ടു ള്ളത്? അദ്ദേഹത്തിന്റെ കണ്ണിന്റെ ന്യൂനത എന്തായിരിക്കും?
d) കണ്ണിന്റെ സമഞ്ജനക്ഷമത കുറയുന്നത് കൊണ്ടുണ്ടാകുന്ന നേതവൈകല്യം ഏത് ?(4)
Answer:
a) സീലിയറി പേശികൾ
b) ആരോഗ്യമുള്ള കണ്ണുകൾക്ക് വ്യക്തമായ കാഴ്ചയ്ക്കുളള കുറഞ്ഞ ദൂരം 25 cm ആണ്.
c) കോൺകേവ് ലെൻസ്, ഹൃസ്വദൃഷ്ടി
d) വെള്ളെഴുത്ത്

Question 34.
പ്രകാശത്തിന്റെ ക്രമരഹിതവും ഭാഗികവുമായ ദിശാവ്യതിയാനമാണ് വിസരണം.
a) ലാബിൽ പ്രകാശത്തിന്റെ വിസരണം ദൃശ്യമാ ക്കുന്നതിനായുള്ള ഒരു പരീക്ഷണം വിശദീക രിക്കുക.
b) കണങ്ങളുടെ വലിപ്പവും വിസരണ നിരക്കും തമ്മിൽ എങ്ങനെ ബന്ധപ്പെട്ടിരിക്കുന്നു?
c) ഉദായസ്തമയ വേളയിൽ സൂര്യനെ ചുവപ്പുനി റത്തിൽ കാണാനുള്ള കാരണം എന്തായി രിക്കും?
d) ഒരു കൊളോയിഡൽ ദ്രവത്തിലൂടെ പ്രകാശം സഞ്ചരിക്കുമ്പോൾ പ്രകാശപാത ദൃശ്യമാകുന്ന പ്രതിഭാസം ഏത് പേരിൽ അറിയപ്പെടുന്നു?
Answer:
a) ഒരു ചതുര പാത്രത്തിൽ മുക്കാൽ ഭാഗത്തോളം ജലം എടുക്കുക. ഒരു ടോർച്ചിൽ നിന്നുള്ള പ്രകാശരശ്മികൾ പാത്രത്തിലെ ജലത്തിലൂടെ ഒരു സ്കീനിൽ പതിപ്പിക്കുന്നു. ലിറ്ററിന് രണ്ട് ഗ്രാം എന്ന് തോതിൽ സോഡിയം സൾഫേറ്റ് പാത്രത്തിലെ ജലത്തിൽ ലയിപ്പിക്കുക. അതി ലേക്ക് ഒന്നോ രണ്ടോ തുള്ളി
ഹൈഡ്രോക്ലോ റിക് ആസിഡ് ചേർക്കുന്നു. ലായനിയിലും സ്ക്രീനിലും പ്രകാശത്തിനു ഉണ്ടാകുന്ന മാറ്റം നിരീക്ഷിക്കാവുന്നതാണ്. പ്രകാശം വിസരണ ത്തിന് വിധേയമാകുന്നതായി കാണാം.

b) കണങ്ങളുടെ വലിപ്പം കൂടുന്നതിനനുസരിച്ച് വിസരണം കൂടുന്നു.

c) ഉദാസ്തമയ വേളകളിൽ സൂര്യനിൽ നിന്നുള്ള പ്രകാശം അന്തരീക്ഷത്തിലൂടെ കൂടുതൽ ദൂരം സഞ്ചരിക്കുമ്പോൾ തരംഗദൈർഘ്യം കുറഞ്ഞ വർണ്ണങ്ങൾ വിതരണം ചെയ്തു നഷ്ടപ്പെട്ടു പോയിരിക്കാം. അതിനാൽ സൂര്യപ്രകാശത്തിൽ അവശേഷിക്കുന്ന തരംഗദൈർഘ്യം കൂടിയ ചുവപ്പു വർണ്ണത്തിൽ ആയിരിക്കും സൂര്യനെ കാണാൻ കഴിയുന്നത്.

d) ടിന്റൽ പ്രഭാവം

Question 35.
ഒരാൾക്ക് അകലെയുള്ള വസ്തുക്കളെ വ്യക്തമായി കാണാൻ സാധിക്കുന്നുണ്ടെങ്കിലും അടുത്തുള്ള വസ്തുക്കളെ കാണാൻ കഴിയുന്നില്ല.
a) ഈ നേത്ര വൈകല്യം ഏതാണ്?
b) കണ്ണിന്റെ ഈ ന്യൂനതയ്ക്ക് കാരണമെന്ത്?
c) ഇദ്ദേഹത്തിന്റെ നേതങ്ങളുടെ നിയർ പോയിന്റ് എവിടെ ആയിരിക്കും?
(25 cm, 25 cm ൽ കൂടുതൽ, 25 cm ൽ കുറവ്)
d) ലെൻസ് ഉപയോഗിച്ച് ഈ നേതവൈകല്യം പരി ഹരിക്കുന്നതിന്റെ രേഖാചിത്രം വരയ്ക്കുക?
Answer:
a) ദീർഘ ദൃഷ്ടി
b) നേത്രഗോളത്തിന്റെ വലിപ്പം കുറയുന്നു. ലെൻസിന്റെ പവർ കുറയുന്നു.
c) 25 cm ൽ കൂടുതൽ
d)

Question 36.
സൂര്യപ്രകാശം അന്തരീക്ഷത്തിലെ ജലകണികയിൽ പതിക്കുന്ന ചിത്രം നൽകിയിരിക്കുന്നു.

a) ചിത്രം പകർത്തിവരച്ച് അപൂർണ്ണമായ ഭാഗം പൂർത്തിയാക്കുക.
b) A, B എന്നിവ ഏത് വർണ്ണങ്ങളാണ്?
c) ജലകണികയിൽ പതന് രശ്മിക്ക് ഉണ്ടായ മാറ്റങ്ങൾ എന്തൊക്കെയാണ്?
d) ഈ പ്രതിഭാസം മുഖേന പ്രകൃതിയിൽ കാണ പ്പെടുന്ന ദൃശ്യം ഏത്?
Answer:
a)
b) A – വയലറ്റ്, B- ചുവപ്പ്
c) പതനരശ്മിക്ക് ജലകണികയ്ക്കുള്ളിൽ രണ്ടു തവണ അപവർത്തനവും ഒരു തവണ ആന്ത പ്രതിപതനവും സംഭവിച്ചു.
d) മഴവില്ല്

Question 37.
ചുവടെ കൊടുത്തിരിക്കുന്നവയ്ക്കുള്ള കാരണം കണ്ടെത്തുക.
a) ചന്ദ്രനിൽ അന്തരീക്ഷം ഇരുണ്ടതാണ്
b) പ്രിസത്തിലൂടെ കടന്നുപോകുമ്പോൾ പ്രകാ ശത്തിന് പ്രകീർണ്ണനം സംഭവിക്കുന്നു.
c) മഞ്ഞുള്ള പ്രഭാതങ്ങളിൽ പ്രകാശത്തിന്റെ പാത ദൃശ്യമാകുന്നു.
d) മഴ പെയ്യുമ്പോൾ താഴേക്ക് പതിക്കുന്ന മഴത്തുള്ളി കൾ സ്ഫടിക ദണ്ഡ് പോലെ കാണപ്പെടുന്നു
Answer:
a) ചന്ദ്രനിൽ അന്തരീക്ഷം ഇല്ലാത്തതിനാൽ പ്രകാ ശത്തിനു വിസരണം സംഭവിക്കുന്നില്ല. അതി
നാൽ ചന്ദ്രനിൽ ആകാശം ഇരുണ്ടതായി തോന്നുന്നു.

b) പ്രകാശം പ്രസത്തിലൂടെ കടന്നു പോകു മ്പോൾ വിവിധ വർണ്ണങ്ങൾക്ക് സംഭവിക്കുന്ന
വ്യതിയാനം വ്യത്യസ്തമായതിനാൽ പ്രകീർ ണ്ണനം സംഭവിക്കുന്നു.

c) ടിന്റൽ പ്രഭാവം

d) വീക്ഷണസ്ഥിരത

The comprehensive approach in SCERT Class 10 Physics Solutions Chapter 1 Sound Waves Important Questions with Answers ensure conceptual clarity.

SSLC Physics Chapter 1 Important Questions Kerala Syllabus

Sound Waves Class 10 Important Questions

Question 1.
Classify the following statements as transverse wave and longitudinal wave.
a) Particles of the medium vibrate perpendicular to the direction of propagation of the wave.
b) Creates pressure difference in the medium
c) Forms in solids, liquids and gases
d) Light waves
e) Seismic waves
f) Forms crest and trough
Answer:
Transverse wave: a, d, f
Longitudinal wave: b, c, e

Question 2.
Complete the word pair
Transverse waves : Crests and troughs
Longitudinal waves : ………………………….
Answer:
Compressions and rarefactions

Question 3.
Bats make use of …………………….. sounds for catching prey.
Answer:
Ultrasonic

Question 4.
What kind of waves are used in sonar? Write one use of these waves in the medical field.
Answer:
Ultrasonic waves, to crush small stones in the kidney.

Question 5.
Given below are graphs of sound waves from different sources that travels through the same medium. Among these, which one has higher frequency? What is the basis of your conclusion?

Answer:
Wave with higher frequency is shown in graph B. As both travel through the same medium, velocity remains the same. But wavelength is inversely proportional to the frequency. ‘B’ has lower wavelength, so B itself has higher frequency.

Question 6.
A sound wave enters water from air. What happens to its wavelength? Why?
Answer:
Wavelength increases. Velocity of sound in water is 1482 m/s and velocity in air is 343 m/s. But the frequency of the sound wave will not change as the medium differs. We know V = f λ. So wavelength should increase.

Question 7.

Given in the graph the points A, B, C, D represents state of vibration of a sound wave. From the below mentioned options which represent the wavelength.
a) Distance between A and C
b) Distance between A and D
c) Distance between A and B
d) Distance between B and C
Answer:
a) Distance between A and C

Question 8.
The wave length of sound travelling in air with the velocity 330 m/s was found to be 60 m. If so
a) Find the frequency of sound.
b) By what name are sounds of such frequency known as?
Answer:
a) V = fλ
330 = f × 60
f = \(\frac{330}{60}\) = 5.5 Hz

b) Infrasonic sound, (frequency is less than 20 Hz)

Question 9.
Velocity of sound in air is 340 m/s. Sound waves of wavelength 0.01 m from a vibrating body reach your ear through air. Will you be able to hear the sound? Justify your answer.
Answer:
V = 340m/s
λ = 0.01m
V = fλ
f = \(\frac{V}{\lambda}\)
f = \(\frac{340}{0.01}\) = 34000 Hz > 20,000 Hz
Human beings cannot hear these sounds.
Audible frequency range of humans is 20 Hz to 20000 Hz.

Question 10.
The tuning fork is stimulated at a frequency of 3 84 Hz and its shaft is pressed to the table at a natural frequency of 230 Hz.
a) Will the table vibrate in this case?
b) Will there be a change in the loudness of the sound? What is the reason?
Answer:
a) The table will vibrate.

b) When the stem of the excited tuning fork is placed on the table, the table vibrates by the impulse of the tuning fork. The more the area of the table, the louder the sound. In this case, the sound became louder because the table also vibrated along with the tuning fork.

Question 11.
A tuning fork with a frequency of 512 Hz is stimulated and held at the mouth of a resonance column. Then there is a slight increase in the pitch of the sound.
a) What is the vibration of the air inside the resonance column called?
b) What is the frequency of the air when the noise level is the highest?
Answer:
a) A forced vibration
b) 512 Hz

Question 12.
Match correctly

Sound Board	Resonance
Resonance Column	Period
Characteristic of wave	Richter scale
Intensity of earthquake	Reflection of sound

Answer:

Sound Board	Reflection of sound
Resonance Column	Resonance
Characteristic of wave	Period
Intensity of earthquake	Richter scale

Question 13.
Write 4 uses of ultrasonic waves.
Answer:

• To crush small stones in the kidneys.
• In physiotherapy.
• To take images of internal organs such as kidney, liver, gall bladder and uterus.
• For cleaning spiral tubes, irregular machine parts, electronic components etc.

Question 14.
What are the uses of sonar?
Answer:

• Sonar is used to find the distance to the underwater objects.
• It is used to measure the depth of the ocean.
• Used to find the location of fish flocks.

Question 15.
A sound signal of 50 kHz is sent to the bottom of a sea. It returned back after 4 s. The velocity of sound in seawater is 1500 m/s. Then,
a) Calculate the depth of the sea
b) What is the wavelength of the wave?
Answer:
a) Suppose the depth of the sea = d
then distance travelled by the wave = 2d
distance = velocity × time
= 1500 × 4
= 6000 m
.’. depth= \(\frac{6000}{2}\) = 3000 m

b) V = fλ
V = 1500 m/s
f = 50kHz = 50000 Hz
λ = \(\frac{v}{f}\) = \(\frac{1500}{50000}\)

Question 16.
A sound was produced. Three seconds later, its echo was heard.
a) What is the distance between the reflecting surface and source? (Speed of sound in air is 340 m/s)
b) Write two methods by which you can reduce the harmful effects of reflection of sound in big halls.
Answer:
a) Distance = Velocity × time
= 340 × 3 = 1020 m
So distance between the source and reflecting surface = \(\frac{1020}{2}\) = 510 m

b) Make the walls rough, provide a large number of ventilators.

Question 17.
a) Sound waves from SONAR in a ship hits the bottom of the sea and comes back after is 1/2 s. Calculate the distance to the bottom of the sea from the ship. (Speed of sound in sea water is 1522 m/s)
b) Which type of sound waves is used in SONAR?
Answer:
a) v = \(\frac{s}{t}\)
v = 1522 m/s
t = \(\frac{1}{2}\)s
s = v × t
= 1522 × \(\frac{1}{2}\)
= 761 m

b) Ultrasonic waves.

Question 18.
Find the reason.
a) The walls are made rough in movie theaters, halls and auditoriums.
b) Soldiers are not allowed to march through the hanging bridge.
Answer:
a) The walls are made rough to avoid the regular reflection of sound. Rough surfaces can absorb sound.

b) If the frequency of vibrations generated as a result of continuous marching is equal to the natural frequency of the bridge, then there is a possibility of the bridge vibrating at a high rate and collapsing. That is, the soldiers are not allowed to march through the hanging bridge to avoid the danger that occurs when the frequency of marching coincides with the natural frequency of the bridge.

Question 19.
The sound signal from a ship on the water surface hits the underwater rock and returns to the ship after 6 s. The speed of sound in sea water is 1522 m/s.
a) What type of wave is transmitted in the sound?
b) What is the cause of the return of the sound signal to the ship?
c) Calculate the distance from the water surface to the rock.
Answer:
a) Longitudinal wave

b) Reflection of sound

c) Speed of sound = total distance traveled / time
Total distance traveled = speed of sound × time
2d = v × t
d = (v × t) / 2 = (1522 × 6) / 2 = 4566 m.

Question 20.
Explain the technique ultra sonography?
Answer:
Ultrasonic waves that travel through body tissues strike and reflect at areas of varying density in the tissues. These waves are converted into electric signals to form an image of the organ. This technique is ultra sonography.

Question 21.
Observe the figure

a) What kind of wave motion is shown in the figure? Illustrate your answer
b) Calculate the frequency of this wave if its velocity is 6420 m/s and wavelength is 6 m.
Answer:
a) Longitudinal wave.
Here pressure difference is plotted against the y axis. Pressure difference forms only in longitudinal waves

b) V = 6420 m / s
λ = 6 m
frequency, f = \(\frac{V}{\lambda}\)
= \(\frac{6420}{6}\) = 1070 Hz

Question 22.
List the waves given below as appropriate.
• Seismic waves
• Light waves
• Sound waves
• Radio waves
• Waves formed on water surface
Answer:

Those which need a medium for propagation	Those which do not need a medium for propagation
• Seismic waves • Sound waves • Waves formed on water surface	• Radio waves • Light waves

Question 23.
Figure shows the distance and displacement of a wave formed in 0.2 s.

a) What is its wavelength?
b) What is the frequency?
c) What is its velocity?
Answer:
a) 5 m
b) f = \(\frac{n}{t}\) = \(\frac{3}{0.2}\) = 15 Hz
c) V = fλ = 15 × 5 = 75 m/s

Question 24.
Observe the figure

a) Which particle is in the same phase of vibration as that of B?
b) What is the distance between these particles called?
c) If the distance between C and E is 25 m, what is the wavelength?
Answer:
a) F
b) wavelength
c) 50 m

Question 25.
Observe the figure

a) How many trough are there?
b) Find out the wavelength?
c) Calculate velocity of the wave if it is travelled within 0.02s.
Answer:
a) 3
b) 4 m
c) f = \(\frac{n}{t}\) = \(\frac{3}{0.02}\) = \(\frac{300}{2}\) = 150 Hz
V = fλ
= 150 × 4 = 600 m/s

Question 26.
A graphic illustration of a wave is given.

a) What type of wave is seen in the picture?
b) What is the amplitude of the wave?
c) If it takes 3 s to go from A to B, what is the frequency?
d) Find the velocity.
Answer:
a) Transverse wave
b) 2 cm
c) frequency = 1 Hz
d) v = fλ = 1 × 6 = 6 m/s

Question 27.
What are the methods to be adopted to escape from Tsunami? Discuss.
Answer:

• Move to a higher plain taking the unusual receding of the sea from the sea shore as a warning of the approaching Tsunami.
• Don’t assume for yourself that the danger is over, instead, wait for the official announcement.
• Try to save your life and not your belongings, as life is precious.
• If caught in Tsunami, try to save yourself by latching onto some floating objects.

Question 28.
Graphic illustration of transmission of two transverse waves A and B through air at a particular time.

If the waves travel this distance in 4 s,
a) Compare the speed of the waves.
b) Write the wavelength of each wave.
e) Which wave has the highest frequency?
d) Write the frequencies of A and B waves.
e) How far will the wave travel in 6 s?
Answer:
a) The speed of the two waves is equal.

b) The wavelength of A = 8 m
The wavelength of B = 4 m.

c) B

d) Frequency of A = 2 cm
Frequency of B = 2 cm

e) Distance traveled in 6 s = (16/4) × 6 = 24 m.

Question 29.
Observe the graphic representation of a wave motion given below.

a) The type of wave is …………………… (Transverse / Longitudinal)
b) Amplitude of the waves is …………………… (1 cm / 2 cm)
c) Wavelength of the wave is …………………… (4m/ 8m)
d) If the waves takes 3 s to reach A, frequency of the waves is …………………… (3 Hz/ 1 Hz )
e) Number of crests is …………………… (3/6)
f) Number of troughs is …………………… (3/2)
g) Speed of the wave is …………………… (8 m/s, 24 m/s )
h) Example for this type of wave is …………………… (Light wave / Sound wave)
Answer:
a) Transverse
b) 2 cm
c) 8 m
d) 1 Hz
e) 3
f) 3
g) 8 m/s (v = f λ = 1 × 8 = 8 m/s)
h) Light wave

Question 30.
SI unit of period is …………………….
Answer:
second

Question 31.
Define frequency with its unit?
Answer:
The number of oscillations in one second is called frequency. The SI unit of frequency is hertz (Hz).

Question 32.
Write the factors that influence the natural frequency of an object?
Answer:

1. Length of the object
2. Size of the object
3. Elasticity
4. Nature of the material

Question 33.
What is meant by the term oscillation?
Answer:
Oscillation is a periodic motion in which an object moves to and fro at regular intervals of time about its equilibrium position.

Question 34.
List whether what happens in each of the following cases is a natural vibration or a forced vibration.
a) Vibration of the stimulated tuning fork
b) The vibration of the sound board during the recovery of the falls
c) The vibration of the air inside the ball when it hits the ball
d) The vibration when the coin falls to the ground
e) The vibration of a steel vessel when it is struck with a spoon
Answer:

Natural Vibration	Forced Vibration
a) Vibration of the stimulated tuning fork	b) The vibration of the sound board during the recovery of the falls
d) The vibration when the coin falls to the ground	c) The vibration of the air inside the ball when it hits the ball
e) The vibration of a steel vessel when it is struck with a spoon

Question 35.
Below is a picture of hexoblades of various lengths fixed on a wooden board.

a) Which blade vibrates in the same way as the blade of C is excited?
b) Why do the two blades vibrate in the same way?
c) What is the vibration of the other blades known as?
Answer:
a) F
b) The natural frequency of both is equal because of resonance.
c) Forced Vibration

Question 36.
What happens to the amplitude of vibrations when the natural frequency of an object matches the frequency of the external forcing object?
Answer:
If the natural frequency of the forcing object and that of the forced object are equal, the objects are said to be in resonance. The objects undergoing resonance will vibrate with maximum amplitude.

Question 37.
Select and write the statements which are suitable for longitudinal waves.
a) The particles of the medium vibrate in a direction perpendicular to the direction of propagation.
b) Propagated by compressions and rarefactions.
c) Sound waves
d) Ripples formed on still water surface.
e) The particles of the medium vibrate in a direction parallel to the direction of propagation.
f) Wavelength is measured as the distance between two consecutive crests or troughs.
Answer:
(b), (c), (e)

Question 38.
Classify the following in the given table

Those which need a medium for propagation	Those which do not need a medium for propagation

a) Radio waves
b) Waves formed on water surface
c) Sound waves
d) Light waves
Answer:

Those which need a medium for propagation	Those which do not need a medium for propagation
b) Waves formed on water surface	a) Radio waves
c) Sound waves	d) Light waves

Question 39.
Electromagnetic waves are ………………… waves, (longitudinal / transverse)
Answer:
transverse

Question 40.
Find the one that doesn’t belong to the group and write the reason.
Amplitude, wavelength, speed of wave, equilibrium position
Answer:
Equilibrium position. Because all others are characteristics of waves.

Question 41.
Write the wave equation. What do each of the letters stand for?
Answer:
Speed of light = frequency × wavelength
v = fλ
where v – the speed of light, f – frequency, λ – the wavelength

Question 42.
Figure shows the distance – displacement graph. The wave is formed in 2s.

a) What is its amplitude?
b) What is its wave length?
c) What is its frequency?
d) What is its velocity?
Answer:
a) 0.2 m
a) 4 m
c) f = \(\frac{n}{t}\) = \(\frac{4}{2}\) = 2Hz
d) V = fλ = 2 × 4 = 8m/s

Question 43.
Distinguish between reverberation and echo.
Answer:
Reverberation is the persistence of sound as a result of multiple reflection. Echo is the phenomenon of hearing a sound by reflection from a surface or obstacle, after hearing the original source.

Question 44.
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A person standing at A claps his hands. Is there any change for occurring echo?
Answer:
Yes, can hear echo. Because the wall w₂ is 18m away from the source. Minimum distance to hear echo is 17m.

Question 45.
A person who bursts a cracker hears its echo after 1 S. How far is the reflecting surface from the person hearing the echo? (speed of sound in air is 340 m/s).
Answer:
Let d be the distance to the reflecting surface. Then the total distance travelled by the sound to the reflecting surface and back will be 2d.
Speed of sound = \(\frac{\text { Total distance travelled }}{\text { Time }}\)
v = \(\frac{2 \mathrm{~d}}{t}\)
d = \(\frac{(\mathrm{v} \times \mathrm{t})}{2}\) = \(\frac{(340 \times 1) \mathrm{m}}{2}\) = 170 m
So the reflecting surface will be 170 m away.

Question 46.
What does seismology mean?
Answer:
Seismology is the study of seismic waves.

Question 47.
Which instrument is used to measure the intensity of earthquake?
Answer:
Richter scale

Question 48.
What are the consequences of earthquakes?
Answer:

• Damage to buildings.
• Traffic routes are disrupted.
• Dams are collapsed.
• Trees fall to the ground.
• It causes loss of life and property.
• It causes tsunami.

Question 49.
Define tsunami.
Answer:
Tsunami is a series of gigantic ocean waves caused by the displacement of large volumes of water in the sea.