One mole of helium is adiabatically expanded from its initial state $(P_i,V_i,T_i)$ to its final state $(P_f,V_f,T_f)$. The decrease in the internal energy associated with this expansion is equal to

(1) $C_V(T_i-T_f)$

(2) $C_P(T_i-T_f)$

(3) $\frac{1}{2}(C_P+C_V)(Ti-T_f)$

(4) $(C_P-C_V)(T_i-T_f)$

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

One mole of an ideal gas at an initial temperature of T K does 6R 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 the gas will be:

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 × 4^0.4 K

(2) 300 × 4^0.4 K

(3) 150 × 4^0.4 K

(4) None of these

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

A gas expands under constant pressure P from volume V₁ toV₂. The work done by the gas is 

(1) $P(V_2-V_1)$

(2) $P(V_1-V_2)$

(3) $P(V_1^{\gamma }-V_2^{\gamma })$

(4) $P\frac{V_1{V}_2}{V_2-V_1}$

When heat is given to a gas in an isobaric process, then 

(1) The work is done by the gas

(2) Internal energy of the gas increases

(3) Both (1) and (2)

(4) None from (1) and (2)

A gas expands 0.25m³ at constant pressure 10³ N/m², the work done is -

(1) 2.5 ergs

(2) 250 J

(3) 250 W

(4) 250 N

A sample of gas expands from volume V₁ to V₂. The amount of work done by the gas is greatest when the expansion is 

(1) Isothermal

(2) Isobaric

(3) Adiabatic

(4) Equal in all cases