An electric kettle is rated 750 W; 220 V. Can this kettle be used in a circuit which has a fuse of current rating 3 A ? Give reason for your answer.
Generated by claude-sonnet-4-6 · 2026-06-15 06:43 · grounding rag
Model Answer
Current drawn by the kettle: $I = P/V = 750/220 \approx 3.41$ A.
No, the kettle cannot be used with a 3 A fuse. Since the kettle draws about 3.41 A, which exceeds 3 A, the fuse will melt (blow) immediately, breaking the circuit. A fuse of rating 5 A should be used instead.
Source: Chapter 11, Section 11.7.1
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Explanation
- The key formula is $I = P/V$. Always calculate current first, then compare with fuse rating.
- The rule: fuse rating must be greater than the current drawn by the appliance.
- Examiners expect: the calculated value (~3.41 A), a clear Yes/No, and the reason (current exceeds fuse rating → fuse blows). Mentioning the correct fuse (5 A) can fetch bonus credit and shows understanding.