Question

A torch bulb is rated 6 V and 750 mA. Calculate the energy consumed by the bulb in 4 hours.

Answer 1

Ratings on the Torch Bulb: 6V and 750 mA.

Voltage across the bulb = V = 6 Volts
Current flowing through the bulb = I = 750 mA = 0.750 A

Power (rated) = Potential * current = V * I
      P = 6 * 0.750 = 4.50 W

Time duration = t = 4 hours
Energy consumed = P * t = 4.50 * 4 = 18 W-hrs
         or  0.018 kWh

Answer 2

Thanks for asking the question.
Given Data:
1. V = 6v
2. I = 750mA = 0.750A
3. P = ?
4. E = ?
5. t = ?
Formula and calculations:
P = V * I
putting the values, we get,
= 6 * 0.750 
=  4.50W
E = P * t
= 4.50 * 4
= 18Whr = 0.018kWh
Hope it helps.