1
WB JEE 2019
+1
-0.25
Two black bodies A and B have equal surface areas are maintained at temperatures 27$$^\circ$$C and 177$$^\circ$$C respectively. What will be the ratio of the thermal energy radiated per second by A to that by B?
A
4 : 9
B
2 : 3
C
16 : 81
D
27 : 177
2
WB JEE 2019
+1
-0.25
What will be the molar specific heat at constant volume of an ideal gas consisting of rigid diatomic molecules?
A
$${3 \over 2}R$$
B
$${5 \over 2}R$$
C
R
D
3R
3
WB JEE 2019
+1
-0.25
Consider the given diagram. An ideal gas is contained in a chamber (left) of volume V and is at an absolute temperature T. It is allowed to rush freely into the right chamber of volume V which is initially vacuum. The whole system is thermally isolated. What will be the final temperature of the equilibrium has been attained?

A
T
B
$${T \over 2}$$
C
2T
D
$${T \over 4}$$
4
WB JEE 2019
+2
-0.5
A horizontal fire hose with a nozzle of cross-sectional area $${5 \over {\sqrt {21} }} \times {10^{ - 3}}{m^2}$$ delivers a cubic metre of water in 10s. What will be the maximum possible increase in the temperature of water while it hits a rigid wall (neglecting the effect of gravity)?
A
$$1^\circ$$C
B
$$0.1^\circ$$C
C
$$10^\circ$$C
D
$$0.01^\circ$$C
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