COMEDK 2025 Evening Shift | Heat and Thermodynamics Question 1 | Physics

The rms velocity of the gas molecule at $327^{\circ} \mathrm{C}$ is same as the rms velocity of the oxygen molecules at $27^{\circ} \mathrm{C}$. If the molecular weight of oxygen is 32 then the molecular weight of the given gas molecule is:

128

COMEDK 2025 Evening Shift

MCQ (Single Correct Answer)

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A given volume of gas at NTP is allowed to expand 6 times of its original volume, first under isothermal condition and then under adiabatic condition. Which of the given statement is correct? [Given $\frac{c_p}{c_v}=\gamma=1.4$ ]

The final pressure after the adiabatic expansion is 1.4 times greater than the final pressure after the isothermal expansion.

The final temperature after the adiabatic expansion is 1.4 times less than the final temperature after the isothermal expansion.

Pressure remains same in both adiabatic and isothermal expansion

The final pressure after the adiabatic expansion is less than the final pressure after the isothermal expansion.

COMEDK 2025 Evening Shift

MCQ (Single Correct Answer)

-0

The rate of heat conduction in the given two metal rods having the same length is found to be the same when the temperature difference between the ends is kept $30^{\circ} \mathrm{C}$ If the area of cross section of the first rod is $8 \times 10^{-2} \mathrm{~m}^2$ then what will be area of cross section of the second rod? [ Given that the ratio of the thermal conductivity of the first rod to that of the second rod is $1: 4$ ]

$2 \times 10^{-2} \mathrm{~m}^2$

$4 \times 10^{-4} \mathrm{~m}^2$

$2 \times 10^{-4} \mathrm{~m}^2$

$4 \times 10^{-2} \mathrm{~m}^2$

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