A gas taken through cyclic process $ABCA$ is shown in figure. If $2.4\,cal.$ of heat is given in the process, what is value of $J$ …… $J/cal$ (mechanical equivalent of heat)?

The $P-V$ diagram for an ideal gas in a piston cylinder assembly undergoing a thermodynamic process is shown in the figure. The process is

An ideal gas goes from state $A$ to state $B$ via three different processes as indicated in the $P-V$ diagram. If $Q_1, Q_2, Q_3$ indicate the heat absorbed by the gas along the three processes and $\Delta U_1, \Delta U_2, \Delta U_3$ 
indicate the change in internal energy along the three processes respectively, then 

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 $E_{int,f}$ ?

When a system is taken from state $i$ to a state $f$ along path $iaf, \,Q = 50\,J$ and $W = 20J.$ Along path $ibf, \,Q = 35J.$ If $W = – 13J$ for the curved return path $f i, Q$ for this path is …… $J$