Question

Question 1 of 7What is the change in internal energy if 90 J of thermal energy is added to asystem, and the system does 30 J of work on the surroundings? Use AU = Q -W.OA. 130 JB. -60 JC. -130 JSUBMITOD. 60 J

Answer 1

Given:

The thermal energy added to the system is Q = 90 J

The work done by the system on the surroundings is W = 30 J

To find the change in internal energy.

Explanation:

According to the first law of thermodynamics, the change in internal energy can be calculated by the formula

$\Delta U=\text{ Q-W}$

On substituting the values, the change in internal energy will be

$\begin{gathered} \Delta U\text{ =90-30} \\ =60\text{ J} \end{gathered}$

Final Answer: The chage in internal energy is 60 J (option D)