When a system is taken from stata a to state b along the path acb as shown in figure, 60 J of heat flows into the system and 30 J of work is done by the system. Along the path adb, if the work done by the system is 10 J, heat flow into the system is

When a system is taken from stata a to state b along the path acb as s

1.	When a system is taken from stata a to state b along the path acb as shown in figure, 60 J of heat flows into the system and 30 J of work is done by the system. Along the path adb, if the work done by the system is 10 J, heat flow into the system is
Answer» 100 J 20 J 80 J 40 J Solution :According to first law of thermofdynamics, For the path ACB, `Q_(acb) = Delta U_(acb) + W_(acb)` `:. Delta U_(acb) = Q_(acb) - W_(acb) = 60 J - 30 J = 30 J` For the path adb, `Q_(adb) = Delta U_(adb) + W_(adb)` As change in internal energy is path INDEPENDENT, so `Delta U_(acb) = Delta U_(adb)` `:. Q_(adb) = 30 J + 10 = 40 J`