Multiple choice

The rating of an electric lamp is 110 V. To use it on 220 V, one will have to use which one of the following?

  1. Transistor

  2. Resistor

  3. Transformer

  4. Generator
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

To operate a 110V lamp on 220V mains, a resistor must be added in series to drop the excess voltage. Using P = V²/R, the lamp's resistance is fixed, so adding external resistance limits current to safe levels. A transformer would be more efficient but wasn't the expected answer.

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