Efficiency requires input and output power identification

Steps:

• Identify input power (P_in) and output power (P_out) from the diagram.
• Recall efficiency formula: η = P_out / P_in × 100% (or as ratio).
• Assume standard labeling where P1 > P0, so P1 = P_in, P0 = P_out.
• Compute η = P0 / P1.

Not enough information: No diagram provided to confirm P0 and P1 labels.

Why D is correct:

• If diagram labels P1 as the efficiency value directly (unusual), it matches.

Why the others are wrong:

• A: Represents fractional loss, not efficiency.
• B: Standard efficiency formula, but incorrect if diagram reverses labels.
• C: Output power alone, ignores input.

Final answer: Not enough information.