Kerala SSLC Physics Question Paper March 2021 with Answers English Medium

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Kerala Syllabus Class 10 Physics Question Paper March 2021 with Answers English Medium

Time: 1½ hrs
Score: 40

Instructions:

• 20 minutes is given as cool-off time.
• Use cool-off time to read the questions and plan your answers.
• Attempt the questions according to the instructions.
• Keep in mind, the score and time while answering the questions.
• The maximum score for questions from 1 to 34 will be 40.

Each question from 1 to 8 carries 1 score.

Question 1.
Choose the least scattered colour in sunlight from the following. (1)
[Violet, Green, Blue, Red]
Answer:
Red

Question 2.
The non-rotating part in a dc motor is _________ (1)
[Armature, Split ring, Graphite Brush]
Answer:
Graphite Brush

Question 3.
Select the odd one from the group. (1)
[Reflection, Dispersion, Refraction, Persistence of Vision]
Answer:
Persistence of Vision

Question 4.
If the object distance and image distance in a concave mirror is 40 cm, what is its focal length? (1)
Answer:

Question 5.
Observe the relations between terms in the first pair and complete the second pair. (1)
CNG: Compressed Natural Gas
LNG: ________________
Answer:
LNG: Liquified Natural Gas

Question 6.
Pick out the one that is not a source of Green Energy. (1)
[Solar Cell, Wind Mill, Biogas, LPG]
Answer:
LPG

Question 7.
Which phenomenon of light is utilized in optical fiber technology? (1)
[Refraction, Total Internal Reflection, Dispersion, Scattering]
Answer:
Total Internal Reflection

Question 8.
The image formed by a convex lens is inverted and diminished. Then the object must be placed: (1)
[At 2F, Beyond 2F, Between F and 2F, At F]
Answer:
Beyond 2F

Each question from 9 to 20 carries 2 scores.

Question 9.
Write the energy change taking place in the given devices.
(a) Incandescent Lamp (1)
(b) Electric Mixie (1)
Answer:
(a) Incandescent lamp: Electrical energy → light energy
(b) Electric mixie: Electrical energy → Mechanical energy

Question 10.
(a) Name the part of a heating equipment in which the electric energy is converted into heat energy. (1)
(b) Name the substance used to make this part. (1)
Answer:
(a) Heating Coil
(b) Nichrome

Question 11.
Explain the difference between short circuits and overloading. (2)
Answer:
Short Circuit:
If the positive and negative terminals of a battery or the two wires from the mains come into contact without the presence of resistance in between, they are said to be in a short circuit.

Overloading:
A circuit is said to be overloaded if the total power of all the appliances connected to it is more than what the circuit can withstand.

Question 12.
Write any two methods to increase the magnetic strength of a current-carrying solenoid. (2)
Answer:

• By increasing the number of turns of the coil.
• By increasing the intensity of the electric current.
• By increasing the area of the cross-section of the core.

Question 13.
Observe the figure of a moving coil loudspeaker.

(a) Name the parts labeled as A and B. (1)
(b) Write the function of the diaphragm in this device. (1)
Answer:
(a) A – Voice Coil
B – Field Magnet
(b) The voice coil, which is placed in the magnetic field, moves to and fro rapidly when electrical pulses pass through it. These movements make the diaphragm vibrate thereby reproducing sound. The diaphragm helps to convert electrical energy into mechanical energy or sound energy.

Question 14.
Write any two relevant first aids to be given in the case of electric shock. (2)
Answer:
After removing the electric connection,

• Raise the temperature of the body by massaging.
• Give artificial respiration.

Question 15.
Explain the following.
(a) Electromagnetic Induction (1)
(b) Induced emf (1)
Answer:
Whenever there is a change in magnetic flux linked with a coil, an emf is induced in the coil. This phenomenon is called electromagnetic induction. The emf induced due to electromagnetic induction is called induced emf.

Question 16.
Observe the figure.

(a) Write the angle of incidence. (1)
(b) Write the relation between the angle of incidence and the angle of reflection. (1)
Answer:
(a) Angle of incidence, i = 90 – 40 = 50°
(b) Angle of incidence = angle of reflection
i = r (by the law of reflection)

Question 17.
When an object is placed at a distance of 30 cm in front of the mirror, an image is obtained at 15 cm on the same side.
(a) Write the values of u and v according to the new cartesian sign convention. (1)
(b) Calculate the focal length of the given mirror. (1)
Answer:
(a) Distance of object, u = -30 cm
Distance of image, v = -15 cm
(b) Focal length of the mirror,

Question 18.
Light falls obliquely from one medium to another as shown in the figure.
[MN is the normal at the point of incidence]

Which of the given medium is the fastest medium for light? Justify your answer. (2)
Answer:
Medium A
Reason: From the figure, the angle of incidence is greater than the angle of refraction as optical density decreases light rays will move away from the normal. So medium A has low optical density. As optical density decreases, the speed of light through the medium increases.

Question 19.
DC is flowing through a solenoid AB. The direction of the current at the end A is anticlockwise.
(a) Write the polarity at the end A. (1)
(b) The solenoid is replaced by a current-carrying conductor. Give the name of the law that helps to determine the direction of the magnetic field produced. (1)
Answer:
(a) North Pole
(b) Maxwell’s right-hand thumb rule/Screw rule.

Question 20.
‘Green energy is the energy of the future’.
Explain the above statement based on the energy crisis. (2)
Answer:
The energy crisis is the consequence of increasing demand and decreasing availability of energy sources. So far future generations, green energy should be maximized since it is eco-friendly and created from nature, we can reduce pollution as well as reduce the use of fossil fuels.

Each question from 21 to 28 carries 3 scores.

Question 21.
2 A current flows through an electric heating device connected to a 230 V supply.
(a) The quantity of charge that flows through the circuit in 5 minutes is: (1)
(i) 10 C
(ii) 60 C
(iii) 600 C
(iv) 6 C
(b) What is the resistance of the device? (1)
(c) Calculate the power of the heating device. (1)
Answer:
(a) Charge Q = I × t
I = 2A
t = 5 m = 5 × 60 s
∴ Q = 2 × 5 × 60 = 600 C
Option (iii) is correct.

(b) R = \(\frac{V}{I}\)
= \(\frac{230}{2}\)
= 115 Ω

(c) P = I²R
= 2² × 115
= 460 W

Question 22.
Three resistances of 4 Ω, 6 Ω, and 12 Ω are given to you.
(a) What is the highest resistance that you can get using all of them? (1)
(b) What is the lowest resistance that can be obtained by using the 6 Ω and 12 Ω resistances? (2)
Answer:
(a) Resistors are connected in series,
R₁ = 4 Ω, R₂ = 6 Ω, R₃ = 12 Ω
R = R₁ + R₂ + R₃
= 4 + 6 + 12
= 22 Ω
(b) The lowest resistance can be made by connecting them parallel.
R₁ = \(\frac{R_1 R_2}{R_1+R_2}=\frac{6 \times 12}{6+12}=\frac{72}{18}\) = 4 Ω

Question 23.
The voltage of electric power generated is increased from 11 kV to 220 kV in power transmission. But the household supply is provided at 230 V.
(a) Write the type of transformer used at the first phase of power transmission. (1)
(b) Write the type of transformer used at the distribution line. (1)
(c) Write any two structural differences between the step-up and step-down transformer. (1)
Answer:
(a) Step up transformer (11 kV to 220 kV)
(b) Step down transformer (11 kV to 230 V)
(c) In step-up transformers, several turns in the primary are less than that in the secondary, and thick wires are used in the primary.
In step-down transformers, several turns in the primary are more than that in the secondary, and thin wires are used in the primary.

Question 24.
The graphical representation of EMF obtained from three electrical sources is given below.

(a) Identify any two sources. (1)
(b) Write any two peculiarities of each of the emf shown in the graph (A) and (B). (2)
Answer:
(a) A – AC generator
B – Battery
C – DC generator

(b) A: Direction changes continuously, emf increases and decreases.
B: Direction does not change, emf is constant.

Question 25.
(a) How fossil fuels are formed? (1)
(b) What are the products obtained by fractional distillation of coal? (2)
Answer:
(a) Fossil fuels are formed by the transformation of plants and animals that went under the earth’s crust millions of years ago. The transformation took place in the absence of air under high pressure and high temperature. Coal, petroleum, and natural gas are fossil fuels. They are not replenished.
(b) Ammonia, coal gas, coal tar, and coke are obtained.

Question 26.
A Rainbow is formed due to the dispersion of sunlight.
(a) What is dispersion? (1)
(b) Write down the changes in the sunlight in the water droplet as the rainbow forms. Explain. (2)
Answer:
(a) It is the splitting up of composite light into its constituent colors.
(b) When sunlight passes through water droplets, it undergoes refraction twice and internal reflection. The light ray emerging from the water droplets which makes the same angle with the line of vision have the same colour. These droplets appear in the form of an arch of a particular color. Thus there is a red colour in the upper edge and violet at the lower edge. All other colors are seen in between depending on their wavelengths.

Question 27.
The critical angle of water with air is shown in the figure.

(a) Define critical angle. (1)
(b) What change in the path of light will be observed if the angle of incidence Is increased from a critical angle? (1)
Answer:
(a) Critical Angle: When a ray of light passes from a medium of greater optical density to that of lower optical density, the angle of incidence at which the angle of refraction becomes 90° is the critical angle.
(b) All the incident rays will be reflected to the same medium without refraction.

Question 28.
The magnification of an image formed in a mirror is -1.
(a) What is the negative sign indicated with the value of magnification? (1)
(b) What is magnification? (1)
(c) Identify the mirror used. (1)
Answer:
(a) If magnification is negative, it means the image formed by the mirror is real and inverted.
(b) Magnification is defined as the ratio of the height of the image to the height of the object.

(c) Concave mirror

Each question from 29 to 34 carries 4 scores.

Question 29.
Observe the figure.

(a) Identify the Generator. (1)
(b) Write the working principle of this generator. (1)
(c) Which type of emf is induced in the armature? (1)
(d) Write the function of the split ring commutator used in this generator. (1)
Answer:
(a) DC generator
(b) Electromagnetic induction
(c) AC
(d) Split rings are used to convert AC into DC.

Question 30.
Analyze the figure to answer the questions.

(a) In which circuit is a varying magnetic field developed around the solenoid? (1)
(b) Which bulb in the circuit glows when the switch is kept on? (1)
(c) Explain whether there is a difference in the intensity of the light of the bulb. (2)
Answer:
(a) Figure B
(b) Both bulbs will glow, but the intensity of bulb B decreases.
(c) When both the switches are getting ON, a varying magnetic field is developed around the coil in fig (B) because of AC, a back emf is induced in it due to self-induction, and the effective voltage across the bulb decreases hence brightness of the bulb decreases.

Question 31.
(a) If the image obtained from a convex lens is erect and enlarged:
(i) Image is formed at: (1)
[Same side of the object/Opposite side of the object]
(ii) Write any one application of this type of image formation. (1)
(b) Write any two characteristics of the image formed by a convex lens when the object is placed at the following positions.
(i) At infinity. (1)
(ii) Between F and 2F. (1)
Answer:
(a) (i) Same side of the object.
(ii) Used in simple microscope/telescope/compound microscope/magnifier/reading lens etc.

Question 32.
Observe the circuit diagram and answer the questions.

(a) Find the effective resistance of the given circuit. (1)
(b) Calculate the current flowing through this circuit. (1)
(c) What is the heat produced in the 100 Ω resistance if the current flows for 10 minutes? (2)
Answer:
(a) R = R₁ + R₂
= 100 + 15
= 115 Ω
(b) I = \(\frac{V}{R}\)
= \(\frac{230}{115}\)
= 2 A
(c) H = I²Rt
= 2² × 100 × 10 × 60
= 240000 J

Question 33.
(a) Write the function of a safety fuse in an electric circuit. (1)
(b) Write any two characteristics of fuse wire. (1)
(c) Write any two precautions to be taken while including fuse wire in a circuit. (2)
Answer:
(a) When excess current flows through the circuit, the heat generated in the fuse wire becomes excessive and the fuse wire will melt, and the circuit will break hence it will protect the device from overcurrent.
(b) Low melting point, high ductility, correct amperage.
(c) The ends of the fuse wire must be connected firmly at appropriate points.
The fuse wire should not project out of the carrier base.

Question 34.
Observe the ray diagram given below.

(a) Redraw the diagram and complete it to get the image. (2)
(b) Write any two characteristics of the image obtained. (2)
Answer:
(a) Object beyond 2F.

(b) Inverted, real, diminished, between F and 2F.