A 120 V, 60 W lamp is to be operated on 220 V a.c. the…

Physics JAMB 2006

A 120 V, 60 W lamp is to be operated on 220 V a.c. the supply mains. calculate the values of non-inductive resistance that would be required to ensure that the lamp is run on current value.

  • 100 Ω
  • 200 Ω checkmark
  • 300 Ω
  • 500 Ω

The correct answer is: B

Explanation

Power of the lamp = 60W = (V2)/R and the voltage rate = 120v.
R = (V2)/60 = (120 X 120)/60 = 240 Ω, the fuse wire that should ensure current does not exceed this value should be rated 200 Ω
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