Question

Which of the following are TRUE for a reversible isothermal process?

(i) ∆U = 0

(ii) ∆H = 0

(iii) Q = W

(iv) ∆T = 0

विकल्प

• (i), (ii), (iv)

• (i), (ii), (iii)

• (i), (iii) and (iv)

• all of these

Answer 1

all of these

Explanation:

For an isothermal process, ∆T = 0

From the first law of thermodynamics, we have ∆U = Q − W .....(i)

Since, in an isothermal reversible process, the system comes back to the initial thermodynamic state, ∆U = 0.

Substituting ∆U = 0 in equation (i), we get

Q = W. ∆H = ∆U + P∆V = ∆U + ∆nRT = 0.

∴ ∆T = 0, ∆U = 0, ∆H = 0 and Q = W