An electric heater of resistance 8 Ω draws 15 A current from a service mains…
2024
An electric heater of resistance 8 Ω draws 15 A current from a service mains for 2 Hrs. What will be the rate at which heat is developed in the heater?
Answer: E. None of the above — The rate at which heat is developed in a heater is given by the formula P = I²R. Substituting I = 15 A and R = 8 Ω, we get P = (15)² × 8 = 225 × 8 = 1800…
- A.
220 watt
- B.
120 watt
- C.
210 watt
- D.
More than one of the above
- E.
None of the above
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Correct answer: E
The rate at which heat is developed in a heater is given by the formula P = I²R. Substituting I = 15 A and R = 8 Ω, we get P = (15)² × 8 = 225 × 8 = 1800 watts. Since none of the given options (220 W, 120 W, 210 W) match this value, and option D suggests 'More than one of the above' (which is not correct), the correct answer is E: None of the above. The time (2 hours) is irrelevant because power is a rate, not total energy.