23. If ΔQ and ΔW represent the heat supplied to the system and the work done on the system respectively

(a)      ΔQ= ΔU + ΔW            (b) ΔQ= ΔU – ΔW (c)      ΔQ=  ΔW-ΔU               (d)   ΔQ= – ΔW-ΔU  Ans. b (6)