Kerala Syllabus Class 10 Physics Model Question Paper Set 3

Practicing Physics Question Paper Class 10 Kerala Syllabus Set 3 English Medium helps identify strengths and weaknesses in a subject.

Physics Class 10 Kerala Syllabus Model Question Paper Set 3

Time: 1 1/2 Hours
Total Score: 40

Instructions:

1. The first 15 minutes is cool-off time. This time is meant for reading the questions and planning your answers.
2. This question paper includes 18 questions in sections A, B, C, D.
3. Questions 5, 11, 13, 14 and 18 contain choices.
4. You need to answer only one of the options provided for each of these choice-based questions.

Section – A

Write down the correct answer by choosing from the given options for questions 1 to 4. Each question carries 1 score. (4 × 1 = 4)

Question 1.
Some statements related to activities to be done to reduce carbon footprint is given
i. Increase domestic energy consumption.
ii. Avoid wasting food.
iii. Use public transport.
iv. Reduce the use of reusable products.

Which are the correct statements related to it?
A. i and ii only
B. iv only
C. All are correct
D. ii and iii only
Answer:
D. ii and iii only

Question 2.
The secondary coil of a transformer has double turns than its primary coil. If the voltage applied in the primary coil is 25 V, what will the voltage be in the secondary? (25 V, 50 V, 2 V, 12.5 V)
Answer:
50 V

Question 3.
Statement: The mechanical advantage of a second-order lever is always greater than one.
Reason: The effort arm and the load arm are equal.
Which of the following is correct?
a) Both the statement and the reason are correct.
b) The statement is correct, but the reason does not justify the statement.
c) Both the statement and the reason are incorrect.
d) The statement is incorrect, but the reason is correct.
Answer:
b) The statement is correct, but the reason does not justify the statement.

Question 4.

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

Section – B

Write down the answers to the questions 5 to 11. Questions 5 and 11 have choices. Each question (7 × 2 = 14)

Question 5.
(A). When an object is placed at a distance of 15 cm from a convex lens, a real image is formed at a distance of 30 cm. What is the focal length of the lens.
Answer:
u = -15 cm,
v = +30 cm
f = \(\frac{u v}{u-v}\)
= \(\frac{-15 \times+30}{-15-+30}=\frac{-15 \times 30}{-45}\) = +10 cm

OR
(B) Height of object is 2 cm and its magnification is -3.
a) Calculate the height of image.
b) What is the nature of image formed?
Answer:
a) h₀ = 2 cm,
m = h_i/h₀ = -3
h_i = -3 × 2 = -6 cm

b) The image formed is real and inverted.

Question 6.
An ophthalmologist gave prescription to a patient to buy spectacles. It is written as + 1.25 and -1.5 D.
a) What has the doctor indicated in the prescription.
b) What are the type of lenses prescribed above?
Answer:
a) Power of lens used in the spectacle.
b) +1.25 D – Convex lens
-1.5 D – Concave lens

Question 7.
A conductor is inserted through a cardboard and kept in a vertical position as in the figure. The portions passing through the cardboard are marked as X and Y.

a) Mark the direction of magnetic field around the points X and Y.
b) Name the law used to find the direction of magnetic field.
Answer:
a)

That is anticlockwise at X and clockwise at Y.

(b) Right hand thumb rule

Question 8.
A force of 30 N was applied on a nail puller to pull a nail. If the mechanical advantage of the nail puller was two, what would be the load applied by the nail?
Answer:
Load
Mechanical advantage = \(\frac{\text { Load }}{\text { Effort }}\)
Mechanical advantage 2
Effort =30N
Load = ?
Load = Mechanical advantage X Effort
= 2 × 30N
= 60N

Question 9.
How many units of energy will be consumed by a 100 W bulb in 30 days, if it works 10 hours everyday?
Answer:
Electric energy (in kilowatt hour)
\(\frac{\text { Power in watt X time in hour }}{\text { 1000 }}\)
Energy consumed by bulb in a day
= \(\frac{1 \times 100 \times 10}{1000}\) = 1 unit
Energy consumed by bulb in a month
= 1 × 30 = 30 units

Question 10.
Classify the following that operate on AC and that on DC. Torch, grinder, microwave oven, emergency lamp
Answer:

Operates on AC	Operates on DC
Grinder	Torch
Microwave oven	Emergency lamp

Question 11.
(A). If 7500 J of heat is produced in 30 s in a conductor having 250 Q resistance, what is the current through the conductor?
Answer:
H = 7500j
t = 30s
R = 250
H = I₂Rt
\(\frac{H}{R t}\) = I²
I = \(\sqrt{\frac{H}{R t}}=\sqrt{\frac{7500}{250 \times 30}}\)
I = √1 = 1A

OR
(B). Calculate the quantity of heat produced when a heating appliance of power 500 W operates for five minutes.
Answer:
p = 500 What
t = 5min = 5 × 60 = 300s
H = Pt = 500 × 300 j = 150000 j

Section – C

Write down the answers to questions 12 to 17. Questions 13 and 14 have ehoices.Each question carries 3 score.(6 × 3 = 18)

Question 12.
The direction of flow of electrons in a magnetic field is represented.

a) Find the direction of force experienced by electrons (Into the paper, out of the paper)
b) State the law which helped to find the direction of force experienced by electrons.
Answer:
a) Out of the paper
b) Fleming’s left hand rule
Hold the thumb, first finger, and second finger of your left hand perpendicular to each other. If the First finger points in the direction of the magnetic field and the second fmger in the direction of the electric current, then the thumb will indicate the direction of the force experienced by the conductor.

Question 13.
(A). 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) 5m
(b) f = \(\frac{n}{t}=\frac{.3}{0.2}\) = 15 Hz
(c) V = fλ = 15 × 5 = 75m/s

(B) a) What do we call a sound with frequency below 20 Hz?
b) What kind of waves are used in SONAR? Give any one use of the wave identified.
c) What is the range of frequency of sounds that humans can hear?
Answer:
a) Infrasonic sound

b) Ultrasonic waves
•Use of ultrasonic waves
. To crush small stones in the kidneys.
. In physiotherapy.
. To take images of internal organs such as
kidney, liver, gall bladder and uterus. (any one)

c) 20 Hz to 20,000 Hz (20kHz)

Question 14
(A). When Newton’s colour disc rotates fast it appears white.
a) Mention the phenomenon related to this?
b) Define this phenomenon.
c) Write another example related to this?
Answer:
a) Persistence of vision

b) When a person sees an object, its image remains in the retina for a time interval of a 1/ 1/6 second. This phenomenon is called persistence of vision.

c) • When a burning incense stick is whirled very fast, a ring of fire can be seen.
• When a torch is rotated very fast, a ring of light is seen.(any one)

OR
(B). The irregular and partial reflection of light is called scattering.
a) Write the factors that influence scattering.
b) Explain the reason why waterfalls appear white in colour even though water is colourless.
c) The sky always appears dark for an astronaut in space. Why?
Answer:
a) Wavelength of light, Size of the particles or molecules.

b) Water appears white in waterfalls due to scattering. When water falls, it forms tiny droplets and bubbles that scatter light in different directions, making it look white or foamy, similar to clouds.

c) As there is no atmosphere in space, light does not undergo scattering. So the sky appears dark instead of blue to an astronaut in space, in the absence of scattered light.

Question 15.
Figure shows a lever.

a) Identify the type of lever shown in figure above? Give an another example for the same type of lever.
b) Explain about the type of lever identified.
c) How does it work?
Answer:
a) First-order lever Example: Scissors

b) First-order lever has the fulcrum positioned between the effort and the load.

c) It works by pivoting around the fulcrum, allowing the effort to move the load. The mechanical advantage depends on the relative distances from the fulcrum to the effort and load.

Question 16.
Energy conservation is very important for a better tomorrow.
a) What do you mean by energy crisis?
b) How do people contribute to energy crisis (any two)
c) Write two actions to reduce your daily electrical energy consumption, (any two)
Answer:
a) Energy crisis is the increase in demand for energy and the decrease in its availability.

b)• Careless use of electricity at homes, transport, and industries
• Over dependence on fossil fuels like coal, oil, and natural gas
• Not making proper use of natural energy resources.
• Slow action and lack of awareness about saving energy

c)• Make a transition to energy-efficient appliances.
• Use LED Bulbs-LEDs use less power and last longer than normal bulbs.
• Turn off electric appliances when not in use- Always switch off fans, lights, and appliances when you leave a room.
• Use natural light during the day

Question 17.
a) In a household electric circuit, to which device does the line coming from the electric pole reach first?
b) What is the key feature of the main switch?
c) What is the necessity of ELCB in a domestic electric circuit?
Answer:
a) The line from the electric pole reaches the watt- hour meter first.

b) It can cut off electricity to the whole house.

c) ELCB helps to disconnect the circuit automatically if there is current leak due to insulation failure or other reasons. This prevents electric shock to those who come in contact with the electric circuit or device.

Section – D

18th question has a choice. Answer any one of the two questions. Each question carries 4 score. (4 × 1 = 4)
Question 18
(A). A schematic diagram of a generator is given:

a) Which type of generator is this? (AC/DC)
b) Name the parts of this generator marked as 1,2, 3, 4.
c) State the working principle of this device.
Answer:
a) AC Generator

b) 1. Field magnet
2. Armature
3. Slip rings
4. Brush

c) Electromagnetic induction: Whenever there is a change in the magnetic flux linked with a coil, an emf is induced in the coil. This phenomenon is electromagnetic induction.

OR
(B).
When 0.1 A current is supplied to the primary of a transformer, 1A current is obtained in the secondary.
a) Which type of transformer is this?
b) If 1000 V is supplied across the primary of this transformer, what will be its power?
c) What will be the power in the secondary?
d) What will be the voltage induced across the secondary?
Answer:
a) Type of transformer: Step-down transformer (secondary current > primary current)

b) Power in primary: P = V × I
= 1000 × 0.1 = 100 W

c) Pow’er in secondary = 100 W (In a transformer with no power loss (Ideal transformer), the power in the primary is equal to the power in the secondary.)

d) Voltage across secondary.
V_s = \(\frac{P}{I_s}=\frac{100}{1}\) = 100V