Question 42
Electrical Energy and PowerAn electric kettle, connected to a 240 V mains, produces 6.0 × 105 J of heat energy to boil a quantity of water in 5 minutes. Find the resistance of the kettle.
- A.14.4 Ω
- B.28.8 Ω
- C.144 Ω
- D.288 Ω
- E.2880 Ω
Show the answer and explanation
Answer: B (28.8 Ω)
Explanation
Power = 6.0 × 105/300 = 2000 W. R = V²/P = 240²/2000 = 28.8 Ω.