# Physics: Thermodynamics

##### 21. Question

A thermally insulted vessel contains 150 g of water at 0°C. Then the air from the vessel is pumped out adiabatically. A fraction of water turns into ice and the rest evaporates at 0°C itself. The mass of evaporated water will be closed to: (Latent heat of vaporization of water = 2.10 × 106 J kg–1 and Latent heat of Fusion of water = 3.36 × 105 J kg–1 )

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##### 22. Question

Following figure shows two processes A and B for a gas. If ΔQA and ΔQB are the amount of heat absorbed by the system in two cases, and ΔUA and ΔUB are changes in internal energies, respectively, then: `Answer`
##### 23. Question

n moles of an ideal gas with constant volume heat capacity CV undergoes an isobaric expansion by a certain volume. The ratio of the work done in the process, to the heat supplied is:

`Answer`
##### 24. Question

One mole of an ideal gas passes through a process where pressure and volume obey the relation P = P0[1 – 1/2 x (V0/V)2] Here P0 and V0 are constants. Calculate the charge in the
temperature of the gas if its volume changes from V0 to 2V0.

`Answer`
##### 25. Question

A cylinder with fixed capacity of 67.2 lit contains helium gas at STP. The amount of heat needed to raise the temperature of the gas by 20°C is : [Given that R = 8.31 J mol –1 K-1

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