Question

When work done by a system was 10 J, the increase in the internal energy of the system was 30 J. The heat 'q' supplied to the system was:

• A. 10 J
• B. 20 J
• C. 30 J
• D. none of these

Answer 1

The correct option is D none of these

Solution:- (D) None of these

From first law of thermodynamics,

$\Delta U=q+W$

$\Rightarrow q=\Delta U-W$

As the work is done by the system and the internal energy is increased.

Therefore,

$W=-10J$

$\Delta U=30J$

$\therefore q=30-(-10)=40J$

Hence the heat supplied to the system is $40J$.