Electrical power and energy transfer

Steps:

• Calculate power dissipated in resistor: P = V × I = 4 V × 0.5 A = 2 W.
• Calculate energy transferred as thermal energy: E = P × t = 2 W × 10 s = 20 J.

Why D is correct:

• Energy as heat follows E = VIt formula, where VIt = 4 × 0.5 × 10 = 20 J, the work done by the electric field converted to thermal energy.

Why the others are wrong:

• A: 12 J from incorrect power like 4 V × 0.3 A (misread current).
• B: 30 J from erroneous power like 3 W × 10 s (arbitrary miscalculation).
• C: 40 J from V × t only (4 V × 10 s), omitting current I.

Final answer: D