NEET UG 2015 — Thermodynamics

One mole of an ideal diatomic gas undergoes a transition from $A$ to $B$ along a path $\mathrm{AB}$ as shown in the figure,  The change in internal energy of the gas during the transition is:

The coefficient of performance of a refrigerator is $5$. If the temperature inside the freezer is $-20^{\circ}C$, the temperature of the surrounding to which it rejects heat is:

The two ends of a metal rod are maintained at temperatures $100 ^{\circ}C$ and $110 ^{\circ}C$ . The rate of heat flow in the rod is found to be $4.0{\text{J s}}^{-1}$ . If the ends are maintained at temperatures $200 ^{\circ}C$ and $210 ^{\circ}C$ , the rate of heat flow will be:

The ratio of the specific heats $\frac{{C}_{P}}{{C}_{v}}= \gamma$ in terms of degrees of freedom (n) is given by:

An ideal gas is compressed to half of its initial volume by means of several processes. Which of the process results in the maximum work done on the gas?

A Carnot engine, having an efficiency of $\eta =\frac{1}{10}$ as heat engine, is used as a refrigerator. If the work done on the system is $10J$, the amount of energy absorbed from the reservoir at a lower temperature is:

$4.0 g$ of a gas occupies $22.4$ liters at NTP. The specific heat capacity of the gas at constant volume is $5.0 J{K}^{-1} mo{l}^{-1}$ . If the speed of sound in this gas at NTP is $952 m{s}^{-1}$ , then the heat capacity at constant pressure is (Take gas constant $R=8.3 J{K}^{-1} mo{l}^{-1}$ )

Figure below shows two paths that may be taken by a gas to go from a state A to a state C.  In process AB, 400 J of heat is added to the system and in process BC, 100 J of heat is added to the system. The heat absorbed by the system in the process AC will be:

On observing light from three different stars $\text{P}$ , $\text{Q}$ and $\text{R}$ , it was found that intensity of violet colour is maximum in the spectrum of $\text{P}$ , the intensity of green colour is maximum in the spectrum of $\text{R}$ and the intensity of red colour is maximum in the spectrum of $\text{Q}$ . If ${T}_{p}, {T}_{Q}$ and ${T}_{R}$ are the respective absolute temperatures of $\text{P}$ , $\text{Q}$ and $\text{R}$ , then it can be concluded from the above observations that :

Two vessels separately contain two ideal gases $A$ and $B$ at the same temperature, the pressure of $A$ being twice that of $B$. Under such conditions, the density of $A$ is found to be $\text{1.5}$ times the density of $B$. The ratio of molecular weights of $A$ and $B$ is