engineering recuitment BHEL Engineer Trainee Mock Test 2025 Thermodynamics First Law of Thermodynamics
A closed system undergoes a process 1-2 for which the values of Q1-2 and W1-2 are +40 kJ and +60 kJ, respectively. If the system is returned to state 1, and Q2-1 is -30 kJ, what is the value of the work W2-1?
1
+20 kJ
2
-50 kJ
3
-80 kJ
4
+40 kJ