Figure depicts the working diagram (P-V graph) of a process corresponding to an ideal gas. Suppose U_A=10J, U_B = 50 J and heat given to the gas during the process BC is 40 J. Determine Internal energy of the gas in the state C.

Figure depicts the working diagram (P-V graph) of a process correspond

1.	Figure depicts the working diagram (P-V graph) of a process corresponding to an ideal gas. Suppose U_A=10J, U_B = 50 J and heat given to the gas during the process BC is 40 J. Determine Internal energy of the gas in the state C.
Answer» Solution :WORK done by the gas during the process BC = AREA below the graph `= -1/2 (20+50) (N )/(m^2) xx(6-2)m^3=-140 J` Now, APPLYING first law of thermodynamics to the process BC, `Delta Q =Delta U+ Delta W` `40J = Delta U+(-140J)` ` thereforeDelta U = 180J` i.e., `(U_c-50 J) = 180 J, or U_c = 230J`