An ideal gas is heated at constant pressure. If $Q$ is the amount of heat absorbed,then the ratio of the work done to the heat absorbed for increasing the internal energy is:

When a system is taken from a state $i$ to $f$ along the path $iaf$ (as shown in the figure),$Q = 50 \, cal$ and $W = 20 \, cal$. Along path $ibf$,$Q = 36 \, cal$.
$(i)$ What is $W$ along path $ibf$?
$(ii)$ If $W = -13 \, cal$ for path $fi$,what is $Q$ for the path $fi$?
$(iii)$ Take $E_{int,i} = 10 \, cal$,then what is $E_{int,f}$?

Two identical adiabatic vessels are filled with oxygen at pressure $P_1$ and $P_2$ $(P_1 > P_2)$. The vessels are interconnected with each other by a non-conducting pipe. If $U_{01}$ and $U_{02}$ denote the initial internal energy of oxygen in the first and second vessel respectively,and $U_{f1}$ and $U_{f2}$ denote the final internal energy values,then:

An engine runs between a reservoir at temperature $200 \,K$ and a hot body which is initially at temperature of $600 \,K$. If the hot body cools down to a temperature of $400 \,K$ in the process,then the maximum amount of work that the engine can do (while working in a cycle) is (the heat capacity of the hot body is $1 \,J/K$).

Two gases $A$ and $B$ have the same initial state $(P, V, n, T)$. Gas $A$ is compressed to $V/8$ by an isothermal process,and gas $B$ is compressed to $V/8$ by an adiabatic process. The ratio of the final pressure of gas $A$ to that of gas $B$ is (Both gases are monoatomic,$\gamma = 5/3$).

$A$ cyclic process $ABCD$ is shown in the given $P-V$ diagram. Which of the following diagrams represents the same process in a $P-T$ graph?