Question

In an adiabatic process, 5000J of work is performed on a system. The system returns to its original state while 1000J of heat is added. The work done during the non-adiabatic process is:

• A. +4000 J
• B. -4000 J
• C. +6000 J
• D. -6000 J

Answer 1

The correct option is B -4000 J

In adiabatic process $dQ=0$

So, $dQ=dU+dW$

$\Rightarrow dU=-dW$

Since work done on system so, work is negative hence,

$\Rightarrow dU=-\left(5000J\right)=5000J$

Now, in non-adjiabatic process $\to$

$\Rightarrow dQ=dU+dW$

$\Rightarrow dW=dQ-dW$ [ Since heat given to syatem so, positive $1000.$ ]

$=1000-5000$

$\Rightarrow dW=-4000J$

Hence, the answer is $-4000J.$