question_answer 3)

An electric bulb is rated 220 V and 100 W. When it is operated on 110 V, the power consumed will be: (a) 100 W                   (b) 75 W                     (c) 50 W                      (d) 25 W

Answer:

Resistance of the electric bulbs,          (P = V2/R) or Power consumed by the bulb when it is operated at 110 V is given by P' =            (V' = 100 V) Thus, (d) is the correct answer.