COMEDK 2025 Afternoon Shift | Heat and Thermodynamics Question 7 | Physics

A monoatomic ideal gas, initially at temperature $T_1$, is enclosed in a cylinder fitted with a frictionless piston. The gas is allowed to expand adiabatically to a temperature $\mathrm{T}_2$ by releasing the piston suddenly. If $L$ and $2 L$ are the lengths of the gas column before and after expansion respectively, then $\frac{T_1}{T_2}$ is

$2^{3 / 2}$

$2^{2 / 3}$

$\left(\frac{1}{2}\right)^{2 / 3}$

$\left(\frac{1}{2}\right)^{3 / 2}$

COMEDK 2025 Afternoon Shift

MCQ (Single Correct Answer)

-0

An ideal gas is expanding such that $P T^2=$ constant. The coefficient of volume expansion of the gas is

$\frac{2}{T}$

$3 T$

$\frac{T}{3}$

$\frac{3}{T}$

COMEDK 2025 Morning Shift

MCQ (Single Correct Answer)

-0

A block of metal A is connected in series with another block of metal B such that the two metal blocks have the same area of cross sections. The thermal conductivity of metal A is K and the free end of metal A is at $80^{\circ} \mathrm{C}$. The temperature of the interface is $60^{\circ} \mathrm{C}$ and the free end of metal B is at $20^{\circ} \mathrm{C}$. Assuming the two metals have the same thickness, the conductivity of metal B is:

$2 K$

$4 K$

$\frac{K}{2}$

$\frac{K}{4}$

COMEDK 2025 Morning Shift

MCQ (Single Correct Answer)

-0

The mean energy per molecule for a diatomic gas is:

$\left(\frac{5}{2}\right) \mathrm{K}_{\mathrm{B}} \mathrm{T}$

$\left(\frac{3}{2}\right) \mathrm{K}_{\mathrm{B}} \mathrm{T}$

$\left(\frac{3}{2 N}\right) \mathrm{K}_{\mathrm{B}} \mathrm{T}$

$\left(\frac{5}{2 N}\right) \mathrm{K}_{\mathrm{B}} \mathrm{T}$

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