Question

A bulb used in a car is rated 12 V , 48 W . find the energy consumed in one minute when the bulb is connected to 6 V battery?

Answer 1

The energy consumed is `720 J`

Explanation:

One of the formulas for power is `P = V^2/R`. Therefore we can find the bulb's resistance using

`R = V^2/P = ((12 V)^2)/(48 W) = 3 Omega`

If we use 6 V instead, the power consumption is `P' = ((6 V)^2)/(3 Omega) = 12 W = 12 J/s`.

In one minute, the energy consumed is `12 J/s*60 s = 720 J`

I hope this helps,
Steve