Multiple choice

A bulb of resistance 22Ω is joined to a battery of 12 V. What is the value of the resistance to be connected in series, with the bulb in order to get current of 0.5 A?

  1. 23.95Ω

  2. 18Ω

  3. 30Ω

  4. 46Ω

Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

If R is the equivalent resistance of the circuit, then R = V/I = 12/ 0.5 = 24 Ω But, R = R1 + R2, ∴ 24 = 22 + R2, ∴ R2 = 2 Ω