Question

Two electic bulbs rated `P_(1)` watt `V` volts and `P_(2)` watt `V` volts are connected in parallel and `V` volts are applied to it. The total power will be
A. `P_(1) + P_(2)` watt
B. `sqrt(P_(1) P_(2))` watt
C. `(P_(1) P_(2))/(P_(1) + P_(2))` watt
D. `(P_(1) + P_(2))/(P_(1) P_(2))` watt

Answer 1

Correct Answer - A
(a) If resistance of bulbs are `R_(1)` and `R_(2)` respectively then
in parallel `(1)/(R_(P)) = (1)/(R_(1)) + (1)/(R_(2))`
`implies (1)/(((V^(2))/(P_(P)))) = (1)/(((V^(2))/(P_(1)))) + (1)/(((V^(2))/(P_(2)))) implies P_(P) = P_(1) + P_(2)`