Science — CBSE Class 10 board question

Option A: 15000 J

Using Joule's law of heating: $H = I^2Rt = (5)^2 \times 20 \times 30 = 25 \times 20 \times 30 = \mathbf{15000 \text{ J}}$

Source: Chapter 11, Section 11.7 (Heating Effect of Electric Current)

Apply the formula $H = I^2Rt$ directly. Students must remember to square the current first — a common error is writing $I \times R \times t$ instead of $I^2 \times R \times t$. This question is a direct application of Joule's law.