Question

Which of the following processes uses the total heat absorbed by system to perform work on the surrounding?

• A. Adiabatic
• B. Isothermal
• C. Isochoric
• D. Isobaric

Hint:

Use the first law and find the process in which the internal energy change is zero.

Answer 1

The Correct Option is B

Step 1: Understanding the Concept
The first law is \(\Delta U=q+w\). If all heat absorbed is used for work, then \(\Delta U=0\).

Step 2: Which Process Has Zero Internal Energy Change
For an ideal gas, \(\Delta U\) depends only on temperature, so \(\Delta U=0\) when temperature is constant.

Step 3: Compare the options
An isothermal process gives \(q=-w\), so the entire heat absorbed becomes work done by the system. This is option (B).
Adiabatic has \(q=0\), isochoric has \(w=0\), and isobaric changes the internal energy.

Final Answer:
In an isothermal process all the heat absorbed is converted into work. \[ \boxed{\text{(B) }\text{Isothermal}} \]