NEET Physics Chapter Wise Mock Test – Transfer of Heat

NEET Physics Chapter Wise Mock Test – Transfer of Heat

Question 1:

Question 2:

Question 3:

Question 4:
Ice starts forming in lake with water at 0°C and when the atmospheric temperature is -10°C. If the time taken for 1 cm of ice be 7 h, then the time taken for the thickness of ice to change from 1 cm to 2 cm, is
(a) 7h
(b) 14h
(c) less than 7h
(d) more than 7h

Question 5:
A wall has two layers A and B, each made of different materials. Both the layers have the same thickness. The thermal conductivity for A is twice that of B and under steady condition, the temperature difference across the wall is 36°C. The temperature difference across the layer A is
(a) 6°C
(b) 12°C
(c) 24°C
(d) 18°C

Question 6:
In a steady state, the temperature at the ends A and B of 20 cm long rod AB are 100°C and 0°C, respectively. The temperature of a point 9 cm from A is
(a) 45°C
(b) 60°C
(c) 55°C
(d) 65°C

Question 7:
A wall has two layers A and B each made of different materials. The layer A is 10 cm thick and B is 20 cm thick. The thermal conductivity of A is thrice that of B. Under thermal equilibrium, temperature difference across the wall is 35°C. The difference of temperature across the layer A is
(a) 20°C
(b) 10°C
(c) 15°C
(d) 5°C

Question 8:

Question 9:

Question 10:
What will be the force developed in steel rod of cross-sectional area 150 mm², which is fixed between two fixed points, if temperature is increased by 20°C? (Assume, a = 10^-5/°C and Y=200 x 10¹¹N/m²)
(a) 200 kN
(b) 400 kN
(c) 600 kN
(d) 800 kN

Question 11:

Question 12:
In similar calorimeters, equal volumes of water and alcohol when poured take 100 s and 74 s respectively to cool from 50°C to 40°C. If the thermal capacity of each calorimeter is numerically equal to volume of either liquid, then the specific heat capacity of alcohol is (Given, relative density of alcohol as 0.8 and specific heat capacity of water as 1 cal/g/°C)
(a) 0.8 cal/g°C
(b) 0.6 cal/g°C
(c) 0.9 cal/g°C
(d) 1 cal/g°C

Question 13:
The ratio of the emissive power to the absorptive power of all substances for the particular wavelength is the same at given temperature. The ratio is known as
(a) the emissive power of a perfectly black body
(b) the emissive power of any type of body
(c) the Stefan’s constant
(d) the Wien’s constant

Question 14:
A black body is at 727°C. It emits energy at a rate which is proportional to
(a) (727)²
(b) (1000)⁴
(c) (1000)²
(d) (727)⁴

Question 15:
A sphere has a surface area of 1.0m² and a temperature of 400 K and the power radiated from it is 150 W. Assuming the sphere is a black body radiator, the power in kilowatt radiated when the area expands to 2.0 m² and the temperature changes to 800 K is
(a) 6.2
(b) 9.6
(c) 4.8
(d) 16

Question 16:
Two spheres of the same material have radii 1 m and 4 m, temperature 4000K and 2000K, respectively. Then, the ratio of energy radiated per second by the first sphere as compared to that by the second is
(a) 4 : 1
(b) 2 : 1
(c) 1 : 1
(d) 1 :4

Question 17:
If a black body radiates 10 cal s^-1 at 227°C, it will radiate at 727°C
(a) 10 cal s^-1
(b) 80 cal s^-1
(c) 160 cal s^-1
(d) None of these

Question 18:

Question 19:

Question 20:
If a body coated black at 600 K surrounded by atmosphere at 300 K has cooling rate the same body at 900 K, surrounded by the same atmosphere, will have cooling rate equal to
(a) 16r₀/3
(b) 8r₀/16
(c) 16r₀
(d) 4r₀

Question 21:
A black body calorimeter filled with hot water cools from 60°C to 50°C in 4 min and 40°C to 30°C in 8 min. The approximate temperature of surrounding is
(a) 10°C
(b) 15°C
(c) 20°C .
(d) 25°C

Question 22:

Question 23:
A black body at 1227°C emits radiations with maximum intensity at a wavelength of 5000Å. If the temperature of the body is increased by 1000°C, the maximum intensity will be observed at
(a) 4000 Å
(b) 5000 Å
(C) 6000 Å
(d) 3000 Å

Question 24:

Question 25:

Direction (Q .Nos.26-30): In each of the following questions a statement of Assertion is given followed by a corresponding statement of Reason just below it. Of the statements mark the correct answer as
(a) Both Assertion and Reason are true and Reason is the correct explanation of Assertion
(b) Both Assertion and Reason are true but Reason is not the correct explanation of the Assertion
(c) Assertion is true but Reason is false
(d) Both Assertion and Reason are false

Question 26:
Assertion (A): A solid sphere of copper of radius R and a hollow sphere of the same material of inner radius r and outer radius R are heated at the same temperature and allowed to cool in the same environment. The hollow sphere cools faster.
Reason (R): Rate of cooling is according to Stefan’s law which is E°∝T⁴.

Question 27:
Assertion (A): Coefficient of absorption of radiation of an ideal black body is 1.
Reason (R): An ideal black emits radiation of all wavelengths.

Question 28:
Assertion (A): It is hotter over the top of fire than at the same distance on the sides.
Reason (R): Air surrounding the fire conducts more heat upwards.

Question 29:
Assertion (A): For higher temperatures, the peak emission wavelength of a black body shifts to lower wavelengths.
Reason (R): Peak emission wavelengths of a black body is proportional to the fourth-power of temperature.

Question 30:
Assertion (A): All elastic materials follow Hook’s law.
Reason (R): Elastomers follow Hook’s law for large strain.

Question 31:
The two ends of a metal rod are maintained at temperatures 100°C and 110°C. The rate of heat flow in the rod is found to be 4.0 J/s. If the ends are maintained at temperatures 200°C and 210°C, the rate of heat flow will be
(a) 44.0 J/s
(b) 16.8 J/s
(c) 8.0 J/s
(d) 4.0 J/s

Question 32:
Steam at 100°C is passed into 20 g of water at 10°C. When water acquires temperature of 80°C, the mass of water present will be (Take, specific heat of water = 1 cal g^-1 ° C^-1 and latent heat of steam = 540 cal g^-1)
(a) 24 g
(b) 31.5g
(c) 42.5g
(d) 22.5g

Question 33:
Certain quantity of water cools from 70°C to 60°C in the first 5 minutes and to 54°C in the next 5 minutes. The temperature of the surroundings is
(a) 45°C
(b) 20°C
(c) 42°C
(d) 10°C

Question 34:
A piece of iron is heated in a flame. If first becomes dull red then becomes reddish yellow and finally turns to white hot. The correct explanation for the above observations is possible by using
(a) Stefan’s law
(b) Wien’s displacement law
(c) Kirchhoff’s law
(d) Newton’s law of cooling

Question 35:

Question 36:

Question 37:

Question 38:
Two slabs A and 6 of different materials but of the same thickness are joined end to form a composite slab. The thermal conductivities of A and 6 are K₁ and K₂ respectively. A steady temperature difference of 12°C is maintained across the composite slab. If K₁=K₂/2 the temperature difference across slabs A is
(a) 4°C
(b) 6°C
(c) 8°C
(d) 10°C

Question 39:
A black body at a temperature of 2600 K has the wavelength corresponding to maximum emission 1200 Å assuming the moon to be perfectly black body. The temperature of the moon, if the wavelength corresponding to maximum emission is 5000 Å, is
(a) 7800 K
(c) 5240 K
(b) 6240 K
(d) 3640 K

Question 40:

Question 41:
An experiment takes 10 min to raise temperature of water from 0°C and 100°C and another 55 min to convert it totally into steam by a stabilised heater. The latent heat of vaporisation comes out to be
(a) 530 cal/g
(b) 540 cal/g
(c) 550 cal/g
(d) 560 cal/g

Question 42:

Question 43:
An aluminium sphere is dipped into water. Which of the following is true?
(a) Buoyancy will be less in water at 0°C than that in water at 4°C
(b) Buoyancy will be more in water at 0°C than that in water at 4°C
(c) Buoyancy in water at 0°C will be same as that in water at 4°C
(d) Buoyancy may be more or less in water at 4°C depending on the radius of the sphere

Question 44:
A sphere, a cube and a thin circular plate, all of same material and of same mass are initially heated to same high temperature
(a) plate will cool fastest and cube the slowest
(b) sphere will cool fastest and cube the slowest
(c) plate will cool fastest and sphere the slowest
(d) cube will cool fastest and plate the slowest

Question 45:
As the temperature is increased, the time period of a pendulum .
(a) increases as its effective length increases even though its centre of mass
(b) decreases as its effective length increases even though its centre of mass still remains at the centre of the bob
(c) increases as its effective length increases due to shifting of centre of mass below the centre of the bob
(d) increases as its effective length remains same but the centre of mass shifts above the centre of the bob

Answers:

Hints And Solutions:

PhysicsChemistryBiology