Question

If voltage across a bulb rated 220 volt-100 watt drops by `2.5 %` of its value, the percentage of the rated value by which the power would decrease is
A. 0.05
B. 0.1
C. 0.2
D. 0.025

Answer 1

`P prop V^(2)` So `(Deltap)/(P)=2(DeltaV)/(V)=5%`