A system is taken from state a to state c by two paths adc and abc as shown in the figure. The internal energy at a is `U_a` = 10J. Along the path adc the amount of heat absorbed `delta Q_1 = 50 J` and the work obtained `delta W_1=20 J` whereas along the path abc the heat absorbed `delta Q_2 = 36 J`. The amount of work along the path abc is

Options

A. 10 J
B. 12 J
C. 36 J
D. 6 J

Answer

D

Explanation

`Delta Q_("adc")=Delta U_("adc")+DeltaW_("adc")`
`implies 50=DeltaU_("adc")+20 implies DeltaU_("adc")=30J`
Now, `DeltaQ_("abc")= DeltaU_("abc") +W_("abc") implies W_("abc")=36-30=6J`.