Question

In an isothermal process, there is

• A. change in temperature
• B. heat supplied is used to do work against external surrounding.
• C. change in internal energy
• D. none of these

Answer 1

Answer: (B)

heat supplied is used to do work against external surrounding.

Answer 2

In an isothermal process, temperature remains constant, i.e., $\Delta T = 0$.
From, $\Delta Q = \Delta U + \Delta W$
$\because \:\:\:\: \Delta U = 0 ,$ $( \because \:\:\: \Delta T = 0)$
Internal energy is constant for an isothermal process.
$\because \:\:\:\: \Delta Q = \Delta W$
$i.e.$, heat supplied in an isothermal change is used to do work against external surrounding.