Thermal Properties of Matter NEET Questions with Solutions

Q: How many questions come from Thermal Properties of Matter in NEET 2027?

You can expect 1 to 2 questions from this chapter in NEET 2027. The chapter has medium PYQ frequency. Calorimetry, latent heat, conduction (especially composite slabs), Stefan-Boltzmann's law and Newton's law of cooling are the favourite topics.

Q: What is the relation between Celsius, Fahrenheit and Kelvin?

T_K equals T_C plus 273.15. T_F equals (9 over 5) times T_C plus 32. So 0 °C is 273.15 K and 32 °F. The size of one Celsius degree equals the size of one Kelvin (no division). One Fahrenheit degree is 5/9 of a Celsius degree.

Q: What is the relation between linear, areal and volumetric expansion coefficients?

For an isotropic solid, the area expansion coefficient beta equals 2 alpha (twice the linear coefficient), and the volume expansion coefficient gamma equals 3 alpha. So alpha : beta : gamma equals 1 : 2 : 3. NEET expects you to know this ratio.

Q: What is specific heat capacity?

Specific heat capacity c is the heat needed to raise the temperature of unit mass of a substance by one Kelvin. Q equals m c delta T. Water has the highest specific heat among common substances, about 4186 J per kg per K, which is why oceans moderate climate.

Q: What is latent heat?

Latent heat L is the heat absorbed (or released) per unit mass during a phase change without a temperature change. Q equals m L. Water has L_fusion equals 334 kJ per kg (ice to water at 0 °C) and L_vaporization equals 2260 kJ per kg (water to steam at 100 °C).

Q: What is Fourier's law of conduction?

Heat flow rate dQ over dt equals minus k A dT over dx. Here k is thermal conductivity, A is cross-section, and dT over dx is the temperature gradient. Steady-state through a slab gives dQ over dt equals k A (T_hot minus T_cold) over L.

Q: What does Stefan-Boltzmann's law say?

Power radiated per unit area by a black body is sigma T to the fourth, where sigma is the Stefan-Boltzmann constant equals 5.67 times 10 to the minus 8 W per m squared per K to the fourth. For a real body multiply by emissivity e. Doubling temperature multiplies radiated power by 16.

Question 1

The Kelvin equivalent of [math] is:

Accepted Answer

233.15 K

Question 2

A metal rod has length [math] at [math] and length [math] at [math]. The linear expansion coefficient is:

Accepted Answer

[math]

Question 3

The relation between linear (α), areal (β) and volumetric (γ) expansion coefficients of an isotropic solid is:

Accepted Answer

[math]

Question 4

Equal masses of water at [math] and [math] are mixed. Ignoring losses, the equilibrium temperature is:

Accepted Answer

[math]

Question 5

Heat needed to convert [math] of ice at [math] to water at [math] is:

Accepted Answer

334 kJ

Question 6

The thermal conductivity of a material has units:

Accepted Answer

W/(m·K)

Question 7

If the temperature of a black body is doubled, the rate of radiation per unit area increases by a factor of:

Accepted Answer

16

Question 8

A body cools from [math] to [math] in 5 minutes. The temperature of the surroundings is [math]. (Newton's cooling assumed) The body cools from [math] to [math] in approximately:

Accepted Answer

8 min

Question 9

Water has a high specific heat capacity. This means:

Accepted Answer

It needs a lot of heat to raise its temperature

Question 10

Two slabs of equal thickness but conductivities [math] and [math] are joined in series. The equivalent conductivity is:

Accepted Answer

[math]

Question 11

The wavelength corresponding to maximum intensity in black body radiation at temperature [math] is given by:

Accepted Answer

[math]

Question 12

100 g of water at 80 °C is mixed with 200 g of water at 20 °C. The equilibrium temperature is:

Accepted Answer

40 °C

Question 13

A metal sphere of radius [math] is heated. Its surface area increases by [math]. The fractional increase in volume is approximately:

Accepted Answer

0.3%

Question 14

Heat conduction is most efficient in:

Accepted Answer

Solids

Question 15

The Fahrenheit equivalent of [math] is:

Accepted Answer

212 °F

Question 16

The amount of heat required to convert [math] of water at [math] to steam at [math] is:

Accepted Answer

113 kJ

Question 17

Newton's law of cooling states that the rate of cooling of a body is proportional to:

Accepted Answer

The temperature difference between body and surroundings

Question 18

A black body at [math] radiates power [math] per m². At [math] the power per m² is:

Accepted Answer

[math]

Question 19

The specific heat of a body of mass [math], when supplied [math] of heat, raised the temperature by [math]. The specific heat is:

Accepted Answer

[math]

Question 20

A composite slab consists of two parts of equal thickness, with thermal conductivities [math] and [math], in series. The equivalent thermal conductivity is:

Accepted Answer

[math]

Question 21

At what temperature does an iron rod become [math] longer than at [math]? Take [math].

Accepted Answer

100 °C

Question 22

The Sun (effective [math] K) peaks at about [math]. A red-giant star with effective [math] K peaks at:

Accepted Answer

1000 nm

Question 23

The latent heat of fusion of ice is the energy required to:

Accepted Answer

Convert ice at 0 °C to water at 0 °C

Question 24

Two rods of the same length and area but different conductivities [math] and [math] are joined in parallel between the same two reservoirs. The effective conductivity of the combination is:

Accepted Answer

[math]

Question 25

At what temperature do the Celsius and Fahrenheit scales coincide (numerical value)?

Accepted Answer

[math]

Question 26

The molar specific heats of an ideal gas at constant pressure and constant volume are related by:

Accepted Answer

[math]

Question 27

A glass jar fits a brass lid tightly. To loosen it, you should:

Accepted Answer

Heat the lid (brass expands more)

Question 28

Steam at 100 °C is passed into 200 g of water at 20 °C until the water is 80 °C. The mass of steam condensed (water [math] = 1 cal/g/°C, L_v = 540 cal/g) is approximately:

Accepted Answer

20 g

Question 29

Newton's law of cooling holds when:

Accepted Answer

The temperature difference is very small

Question 30

The specific heat of water in SI units is approximately:

Accepted Answer

4186 J/(kg·K)

Thermal Properties of MatterNEET Physics · Class 11 · NCERT Chapter 10

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Thermal Properties of MatterNEET Physics · Class 11 · NCERT Chapter 10

1NEET 2018EasyThe Kelvin equivalent of −40°C is:

2NEET 2020MediumA metal rod has length 1m at 20°C and length 1.001m at 70°C. The linear expansion coefficient is:

3NEET 2022EasyThe relation between linear (α), areal (β) and volumetric (γ) expansion coefficients of an isotropic solid is:

4NEET 2017MediumEqual masses of water at 80°C and 20°C are mixed. Ignoring losses, the equilibrium temperature is:

5NEET 2021MediumHeat needed to convert 1kg of ice at 0°C to water at 0°C is:

6NEET 2019MediumThe thermal conductivity of a material has units:

7NEET 2024MediumIf the temperature of a black body is doubled, the rate of radiation per unit area increases by a factor of:

8NEET 2018MediumA body cools from 80°C to 60°C in 5 minutes. The temperature of the surroundings is 20°C. (Newton's cooling assumed) The body cools from 60°C to 40°C in approximately:

9NEET 2023EasyWater has a high specific heat capacity. This means:

10NEET 2020MediumTwo slabs of equal thickness but conductivities K and 2K are joined in series. The equivalent conductivity is:

11NEET 2022MediumThe wavelength corresponding to maximum intensity in black body radiation at temperature T is given by:

12NEET 2017Medium100 g of water at 80 °C is mixed with 200 g of water at 20 °C. The equilibrium temperature is:

13NEET 2021MediumA metal sphere of radius r is heated. Its surface area increases by 0.2%. The fractional increase in volume is approximately:

14NEET 2019EasyHeat conduction is most efficient in:

15NEET 2024EasyThe Fahrenheit equivalent of 100°C is:

16NEET 2018MediumThe amount of heat required to convert 50g of water at 100°C to steam at 100°C is:

17NEET 2020EasyNewton's law of cooling states that the rate of cooling of a body is proportional to:

18NEET 2022MediumA black body at 300K radiates power P1​ per m². At 600K the power per m² is:

19NEET 2017MediumThe specific heat of a body of mass 200g, when supplied 4000J of heat, raised the temperature by 50°C. The specific heat is:

20NEET 2023MediumA composite slab consists of two parts of equal thickness, with thermal conductivities K1​ and K2​, in series. The equivalent thermal conductivity is:

21NEET 2014MediumAt what temperature does an iron rod become 0.1% longer than at 0°C? Take αFe​=1.0×10−5K−1.

22NEET 2024MediumThe Sun (effective T≈5800 K) peaks at about 500nm. A red-giant star with effective T=2900 K peaks at:

23NEET 2019MediumThe latent heat of fusion of ice is the energy required to:

24NEET 2021MediumTwo rods of the same length and area but different conductivities K and 3K are joined in parallel between the same two reservoirs. The effective conductivity of the combination is:

25NEET 2018EasyAt what temperature do the Celsius and Fahrenheit scales coincide (numerical value)?

26NEET 2020MediumThe molar specific heats of an ideal gas at constant pressure and constant volume are related by:

27NEET 2022MediumA glass jar fits a brass lid tightly. To loosen it, you should:

28NEET 2017HardSteam at 100 °C is passed into 200 g of water at 20 °C until the water is 80 °C. The mass of steam condensed (water c = 1 cal/g/°C, L_v = 540 cal/g) is approximately:

29NEET 2023MediumNewton's law of cooling holds when:

30NEET 2016EasyThe specific heat of water in SI units is approximately:

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