Physics Thermodynamics

Two moles of an ideal gas with $\frac{C_P}{C_V}=\frac{5}{3}$ $\frac{{}_{}}{{}_{}}\frac{}{}$ are mixed with 3 moles of another ideal gas with $\frac{C_P}{C_V}=\frac{4}{3}$ $\frac{{}_{}}{{}_{}}\frac{}{}$ . The value of $\frac{C_P}{C_V}$ $\frac{{}_{}}{{}_{}}$ for the mixture is:

Under an adiabatic process, the volume of an ideal gas gets doubled. Consequently the mean collision time between the gas molecule changes from ${\tau }_1$ to ${\tau }_2$ . If $\frac{C_p}{C_v}=\gamma$ for the gas then a good estimate for $\frac{{\tau }_2}{{\tau }_1}$  is given by
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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)

Two ideal Carnot engines operate in cascade (all heat given up by one engine is used by the other engine to produce work) between temperatures, $T_1$ and $T_2$ . The temperature of the hot reservoir of the first engine is $T_1$ and the temperature of the cold reservoir of the second engine is $T_2$ . $T$ is temperature of the sink of first engine which is also the source for the second engine. How is $T$ related to $T_1$ and $T_2$ , if both the engines perform equal amount of work?
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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)

In thermodynamics, heat and work are :

The volume V of an enclosure contains a mixture of three gases, 16 g of oxygen, 28 g of nitrogen and 44 g of carbon dioxide at absolute temperature T. Consider R as universal gas constant. The pressure of the mixture of gases is :

Two Carnot engines A and B operate in series such that engine A absorbs heat at T? and rejects heat to a sink at temperature T. Engine B absorbs half of the heat rejected by Engine A and rejects heat to the sink at T?. When work done in both the cases is equal, the value of T is:
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One mole of an ideal gas is taken through an adiabatic process where the temperature rises from 27°C to 37°C. If the ideal gas is composed of polyatomic molecule that has 4 vibrational modes, which of the following is true? [R = 8.314 J mol⁻¹K⁻¹]

A body takes 4 min. to cool from 61°C to 59°C. If the temperature of the surroundings is 30°C, the time taken by the body to cool from 51°C to 49°C is:
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