1
COMEDK 2025 Morning Shift
MCQ (Single Correct Answer)
+1
-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:
A
$2 K$
B
$4 K$
C
$\frac{K}{2}$
D
$\frac{K}{4}$
2
COMEDK 2025 Morning Shift
MCQ (Single Correct Answer)
+1
-0
The mean energy per molecule for a diatomic gas is:
A
$\left(\frac{5}{2}\right) \mathrm{K}_{\mathrm{B}} \mathrm{T}$
B
$\left(\frac{3}{2}\right) \mathrm{K}_{\mathrm{B}} \mathrm{T}$
C
$\left(\frac{3}{2 N}\right) \mathrm{K}_{\mathrm{B}} \mathrm{T}$
D
$\left(\frac{5}{2 N}\right) \mathrm{K}_{\mathrm{B}} \mathrm{T}$
3
COMEDK 2025 Morning Shift
MCQ (Single Correct Answer)
+1
-0
The ratio of specific heat capacities at constant pressure to that at constant volume for a given mass of a gas is $\frac{5}{2}$. If the percentage increase in volume of the gas while undergoing an adiabatic change is $\frac{3}{2}$, then the percentage decrease in pressure will be:
A
$\frac{15}{4}$
B
$\frac{3}{5}$
C
$\frac{4}{15}$
D
$\frac{5}{3}$
4
COMEDK 2025 Morning Shift
MCQ (Single Correct Answer)
+1
-0

A sample of an ideal gas is taken through the cyclic process ABCA as shown in figure below. It absorbs 60 J of heat during the part AB and rejects 80 J of heat during CA . There is no heat exchanged during the process $\mathrm{BC} . \mathrm{A}$ work of 40 J is done on the gas during the part BC . If the internal energy of the gas at A is 1450 J , then the work done by the gas during the part CA is:

COMEDK 2025 Morning Shift Physics - Heat and Thermodynamics Question 9 English

A
10J
B
20J
C
40J
D
30J
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