Power delivered

Power delivered by a dc circuit element can be calculated using the relation

Using above relation we can say

1. The rate of heat generated in a wire is doubled when both the radius & length of the wire is doubled.

2. For constant voltage, the time taken to boil water by a heater directly varies with its resistance. i.e. t ∝ R.

3. Equivalent power of two bulbs of same voltage rating connected to a supply of voltage equal to voltage rating of either is

(i)        (ii) P_parallel = P₁ + P₂