Free Physics12 Practice Test - IAS 

Question 1

A solid cube just gets completely immersed in water when a 0.2 kg mass is placed on it. If the mass is removed, the cube is 2 cm above the water level. What is the length of each side of the cube?

A. 12 cm
B. 10 cm
C. 8 cm
D. 6 cm

SOLUTION

Solution : B

Option:(b)

Question 2

A hollow sphere of radius R, a hollow cube of side R and a thin circular plate of radius R, made up of the same material, are all heated to 20° C above room temperature. When left to cool in the room, which of them will reach the room temperature first?

A. Circular plate
B. Cube
C. Sphere
D. All of them will reach the room temperature at the same time

SOLUTION

Solution : C

Option:(c)

Question 3

Assertion (A): With the increase of temperature, the viscosity of glycerine increases.
Reason (R): Rise of temperature increases kinetic energy of molecules.
Codes

A. Both A and R are true and R is the correct explanation of A
B. Both A and R are true but R is not a correct explanation of A
C. A is true but R is false
D. A is false but R is true

SOLUTION

Solution : A

Option:(a)

Question 4

Consider the following statements
1.Light of longer wavelength is scattered much more than the light of shorter wavelength.
2.The speed of visible light in water is 0.95 times the speed in vacuum.
3.Radio waves are produced by rapidly oscillating electrical currents.
4.To detect the overspeeding vehicles, police use the Doppler effect of reflected short radio waves.
Which of these statements are correct?

A. 1 and 2
B. 1 and 3
C. 2 and 4
D. 3 and 4

SOLUTION

Solution : D

Option:(d)

Question 5

If a potato is placed on a pure paper plate which is white and unprinted and put in a microwave oven, the potato heats up but the paper plate does not. This is because

A. potato is mainly made up of starch whereas paper is mainly made up of cellulose
B. potato transmits microwaves whereas paper reflects microwaves
C. potato contains water whereas paper does not contain water
D. potato is a fresh organic material whereas paper is a dead organic material

SOLUTION

Solution : C

Option:(c)

Question 6

Which one of the following reflects back more sunlight as compared to other three?

A. Sand desert
B. Paddy crop land
C. Land covered with fresh snow
D. Prairie land

SOLUTION

Solution : C

Option:(C)

Question 7

What is the principle by which a cooling system (Radiator) in a motor car works?

A. Conduction only
B. Convection
C. Radiation only
D. Both convection and radiation

SOLUTION

Solution : D

Option:(d)

Question 8

Indiscriminate disposal of used fluorescent electric lamps causes mercury pollution in the environment. Why is mercury uses in the manufacture of these lamps?

A. A mercury coating on the inside of the lamp makes the light bright white
B. When the lamp is switched on, the mercury in the lamp causes the emission of ultra-violet radiations
C. When the lamp is switched on, it is the mercury which converts the ultra-violet energy into visible light
D. None of the statements given above is correct about the use of mercury in the manufacture of fluorescent lamps

SOLUTION

Solution : B

Option:(b)

Question 9

Assertion (A): A piece of copper and a piece of glass are heated to the same temperature. When touched, thereafter, the copper piece appears hotter than the glass piece.
Reason (R) : The density of copper is more than that of glass.
Codes

A. Both A and R are true and R is the correct explanation of A
B. Both A and R are true but R is not a correct explanation of A
C. A is true but R is false
D. A is false but R is true

SOLUTION

Solution : B

Option:(b)

Question 10

Assertion (A): A stick is dipped in water in a slanting position. If observed sideways, the stick appears short and bent at the surface of water.
Reason (R): A light coming from the stick undergoes scattering from water molecules giving the stick a short and bent appearance.
Codes

A. Both A and R are true and R is the correct explanation of A
B. Both A and R are true but R is not a correct explanation of A
C. A is true but R is false
D. A is false but R is true

SOLUTION

Solution : C

Option:(c)

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