**Past NEET Questions on Thermal Properties of Matter**

#### Class 11 Chapter

**Question 4)**** [NEET 2016]** A blackbody is at a temperature of 5760 K. The energy of radiation emitted by the body at wavelength 250 nm is U1, at wavelength 500 nm is U2 and that at 1000 nm is U3. Wien's constant, b = 2.88 x 10^{6} nmK. Which of the following is correct?

(a) U3 = 0

( b) U1 > U2

(c ) U2 > U1

(d) U1 = 0

**Answer:** Correct option is (c)

**Question 6) ****[NEET 2016]** A piece of ice falls from a height h so that it melts completely. Only one-quarter of the heat produced is absorbed by the ice and all energy of ice gets converted into heat during its fall. The value of h is [given, latent heat of ice is 3.4x10^{5 } J/kg and g = 10 N/kg.]

(a) 544 km

(b) 136 km

(c ) 68 km

(D) 34 km

**Answer:** Correct option is (b)

**Question 25)**** [AIPMT 2014]** 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

**Answer:** Correct option is (a)

**Question 24) [AIPMT 2014]** Steam at 100°C is passed into 20 g of water at 10°C. When water acquires a 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})

- 24 g
- 31.5 g
- 42.5 g
- 22.5 g

**Answer: **Correct option is (d) 22.5 g