O Levels Physics (5054)•5054/11/O/N/21
Explanation
Total energy from parallel lamps' power and time
Steps:
- Each lamp consumes 100 W; in parallel, total power is 200 W.
- Convert time: 36 minutes = 0.6 hours.
- Calculate energy: 200 W × 0.6 h = 120 Wh = 0.12 kWh.
- Matches option C.
Why C is correct:
- Energy E = P × t formula, where total P = 200 W for parallel connection and t = 0.6 h, yields 0.12 kWh.
Why the others are wrong:
- A: Uses one lamp's power (100 W) only, ignoring parallel total.
- B: Halves total power or miscalculates time, yielding 60 Wh.
- D: Treats time as 10 hours or ignores kWh conversion, far too high.
Final answer: C
Topic: Uses of electricity
Practice more O Levels Physics (5054) questions on mMCQ.me