1
COMEDK 2023 Evening Shift
MCQ (Single Correct Answer)
+1
-0

If the ratio of specific heat of a gas at constant pressure to that at constant volume is $$\gamma$$, the change in internal energy of a mass of a gas when the volume changes from $$\mathrm{V}$$ to $$3 \mathrm{~V}$$ at constant pressure is

A
$$\frac{R}{(\gamma-1)}$$
B
$$2 P V$$
C
$$\frac{2 P V}{\gamma}$$
D
$$\frac{2 P V}{(\gamma-1)}$$
2
COMEDK 2023 Evening Shift
MCQ (Single Correct Answer)
+1
-0

The molecules of a given mass of a gas have root mean square speed of $$120 \mathrm{~m} / \mathrm{s}$$ at $$88^{\circ} \mathrm{C}$$ and 1 atmospheric pressure. The root mean square speed of the molecules at $$127^{\circ} \mathrm{C}$$ and 2 atmospheric pressure is

A
105.2 m/s
B
1.443 m/s
C
126.3 m/s
D
88/127 m/s
3
COMEDK 2023 Evening Shift
MCQ (Single Correct Answer)
+1
-0

Two black bodies $$\mathrm{P}$$ and $$\mathrm{Q}$$ have equal surface areas and are kept at temperatures $$127^{\circ} \mathrm{C}$$ and $$27^{\circ} \mathrm{C}$$ respectively. The ratio of thermal power radiated by A to that by B is

A
$$81: 256$$
B
$$177: 127$$
C
$$127: 177$$
D
$$256: 81$$
4
COMEDK 2022
MCQ (Single Correct Answer)
+1
-0

If heat engine is filled at temperature 27$$^\circ$$C and heat of 100 k cal is taken from source at temperature 677$$^\circ$$C. Work done (in J) is

A
$$0.28\times10^6$$
B
$$2.8\times10^6$$
C
$$28\times10^6$$
D
$$0.028\times10^6$$
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