In an adiabatic expansion of a gas initial and final temperatures are T1 and T2 respectively, then the change in internal energy of the gas is -

(1) $\frac{R}{\gamma -1}\left({T}_{2}-{T}_{1}\right)$

(2) $\frac{R}{\gamma -1}\left({T}_{1}-{T}_{2}\right)$

(3) R(T1T2)

(4) Zero

Concept Questions :-

First law of thermodynamics
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Difficulty Level:

Helium at 27°C has a volume of 8 litres. It is suddenly compressed to a volume of 1 litre. The temperature of the gas will be [γ = 5/3]

(1) 108°C

(2) 9327°C

(3) 1200°C

(4) 927°C

Concept Questions :-

Types of processes
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Difficulty Level:

A cycle tyre bursts suddenly. This represents an

(1) Isothermal process

(2) Isobaric process

(3) Isochoric process

Concept Questions :-

Types of processes
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Difficulty Level:

One mole of helium is adiabatically expanded from its initial state $\left({P}_{i},{V}_{i},{T}_{i}\right)$ to its final state $\left({P}_{f},{V}_{f},{T}_{f}\right)$. The decrease in the internal energy associated with this expansion is equal to

(1) ${C}_{V}\left({T}_{i}-{T}_{f}\right)$

(2) ${C}_{P}\left({T}_{i}-{T}_{f}\right)$

(3) $\frac{1}{2}\left({C}_{P}+{C}_{V}\right)\left(Ti-{T}_{f}\right)$

(4) $\left({C}_{P}-{C}_{V}\right)\left({T}_{i}-{T}_{f}\right)$

Concept Questions :-

Types of processes
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Difficulty Level:

A diatomic gas initially at 18°C is compressed adiabatically to one-eighth of its original volume. The temperature after compression will be

(1) 10°C

(2) 887°C

(3) 668 K

(4) 144°C

Concept Questions :-

Types of processes
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Difficulty Level:

During an adiabatic process, the pressure of a gas is found to be proportional to the cube of its absolute temperature. The ratio Cp/Cv for the gas is

(1) $\frac{3}{2}$

(2) $\frac{4}{3}$

(3) 2

(4) $\frac{5}{3}$

Concept Questions :-

Types of processes
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Difficulty Level:

One mole of an ideal gas at an initial temperature of T K does 6 R joules of work adiabatically. If the ratio of specific heats of this gas at constant pressure and at constant volume is 5/3, the final temperature of gas will be -

(1) (T + 2.4)K

(2) (T – 2.4)K

(3) (T + 4)K

(4) (T – 4)K

Concept Questions :-

Types of processes
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Difficulty Level:

We consider a thermodynamic system. If ΔU represents the increase in its internal energy and W the work done by the system, which of the following statements is true ?

1. ΔU = –W in an adiabatic process

2. ΔU = W in an isothermal process

3. ΔU = –W in an isothermal process

4. ΔU = W in an adiabatic process

Concept Questions :-

Types of processes
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Difficulty Level:

The volume of a gas is reduced adiabatically to $\frac{1}{4}$ of its volume at 27°C, if the value of γ = 1.4, then the new temperature will be -

(1) 350 × 40.4 K

(2) 300 × 40.4 K

(3) 150 × 40.4 K

(4) None of these

Concept Questions :-

Types of processes
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Difficulty Level:

For an adiabatic expansion of a perfect gas, the value of $\frac{\Delta P}{P}$ is equal to

(1) $-\sqrt{\gamma }\frac{\Delta V}{V}$

(2) $-\frac{\Delta V}{V}$

(3) $-\gamma \frac{\Delta V}{V}$

(4) $-{\gamma }^{2}\frac{\Delta V}{V}$

Concept Questions :-

Types of processes