A carnot engine having an efficiency of $${1 \over {10}}$$ is being used as a refrigerator. If the work done on the refrigerator is 10 J, the amount of heat absorbed from the reservoir at lower temperature is :

Consider a mixture of n moles of helium gas and 2n moles of oxygen gas (molecules taken to be rigid) as an ideal gas. Its C_P/C_V value will be :

The plot that depicts the behavior of the mean free time t (time between two successive collisions) for the molecules of an ideal gas, as a function of temperature (T), qualitatively, is:
(Graphs are schematic and not drawn to scale)

A thermodynamic cycle xyzx is shown on a V-T diagram. The P-V diagram that best describes this cycle is :
(Diagrams are schematic and not to scale)