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 (i) a 12 V battery, and (ii) a 6 V battery.

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Answer 1

Energy = power × time

first we have to find the current

power = current × voltage

48 = I × 12

l = 48/12

l = 4 A

now,

i) P = Vl

= 12 × 4

= 48 w

energy = 48 × 1

= 48 joules

ii) this ia 6 v

so this would be 28 joules because 6v is half in 12 v...