Thermodynamics ...

Find coefficient of performance, If in a mechanical refrigerator, the lower temperature coils of evaporator are $$-23^oC$$ compressed gas in condenser has a temperature of $$77^oC$$. The coefficient of performance is 

In a thermodynamic system, $$Q$$ represents the energy transferred to or from a system by heat and $$W$$ represents the energy transferred to or from a system by work
$$Q > 0$$ and $$W=0$$
$$Q < 0$$ and $$W=0$$
$$W > 0$$ and $$Q=0$$
$$W > 0$$ and $$Q=0$$
Which of the above will lead to an increase in the internal energy of the system?

In an isobaric process, the work done by a di-atomic gas is $$10$$J, the heat given to the gas will be?

Air in a sealed syringe is slowly compressed by moving the piston. The temperature of the air stays the same. Which statement about the air is correct?

5,6 L of the gas at STP is adiabatically compressed. to 0.7 L taking initial Temperature $$ T_1 $$ the W.D in the process is 

Which of the following is a slow process?

A sample of an ideal gas is taken through the cyclic process $$abca$$ as shown in the figure. The change in the internal energy of the gas along the path $$ca$$ is -  $$180J$$. The gas absorbs $$250 J$$ of heat along the path ab and $$60J$$  along the path $$bc$$. The work done by the gas along the path $$abc$$ is : 

An ideal gas is compressed adibatically to (8/27) of its original volume. if $$ \gamma = 5/3 $$ and rise in its temperature if $$ 375^0 C $$ , its initial temperature is 

Five moles of an ideal monatomic gas with an initial temperature of $$150^0C$$ expand and in the process absorb $$1500J$$ of heat and does $$2500J$$ of work. The final temperature of the gas in $$^0C$$  (ideal gas constant, $$R=8.314JK^{-1}mol^{-1}$$ ).

Two identical systems, with heat capacity at constant volume that varies as $$C_v=bT^3$$ (where $$b$$ is a constant) are thermally isolated. Initially, one system is at a temperature $$100K$$ and the other is at $$200K$$. The systems are then brought to thermal contact and the combined system is allowed to reach thermal equilibrium. The final temperature (in K) of the combined system will be