A sample of an ideal gas is contained in a cy | vedclass

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(A) When the volume of an ideal gas is suddenly decreased,the process is adiabatic because there is no time for heat exchange with the surroundings $(

Vedclass · Accepted Answer

$I$ and $II$ only

Vedclass · Answer

(A) When the volume of an ideal gas is suddenly decreased,the process is adiabatic because there is no time for heat exchange with the surroundings $(Q = 0)$.According to the first law of thermodynamics,$\Delta U = Q - W$. Since the gas is compressed,work is done on the gas $(W  0)$.Since the internal energy of an ideal gas is directly proportional to its temperature $(U \propto T)$,the temperature of the gas increases. Thus,statement $III$ is false.The average kinetic energy of gas atoms is proportional to the absolute temperature $(KE_{avg} = \frac{3}{2}kT)$,so the kinetic energy increases. Thus,statement $I$ is true.Because the volume is decreased and the speed of the atoms increases,the atoms collide with the walls of the cylinder more frequently,leading to an increase in pressure. Thus,statement $II$ is true.Therefore,statements $I$ and $II$ are true.

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