Question

In a closed insulated container a liquid is stirred with a paddle to increase the temperature which of the following is true?

(a) ΔE = W ≠ 0, q = 0

(b) ΔE = W = q ≠ 0

(c) ΔE = 0, W = q ≠ 0

(d) W = 0, ΔE = q ≠ 0

Answer 1

The correct option is: (a) ΔE = W ≠ 0, q = 0

Explanation:

The mathematical form of first law of thermodynamics : q = ΔE + W

Since the system is closed and insulated, q = 0

Paddle work is done on system. 

. ^.. W ≠ 0.

Temperature and hence internal energy of the system increases

. ^.. ΔE ≠ 0.