Question

A torch bulb is rated 5v And 500mA. Calculate energy consumed when it is lighted for 2.5 hours. Unit kwh

Answer 1

Answer:

2.5*60*60*4=36000J/s or 10J/hr

Answer 2

Energy consumed is - 6.25*10^-3 kWh

Given values in question are - voltage - 5V, current - 500mA = 0.5 Ampere, time - 2.5 hours

First of all, the power consumed will be calculated by the help of formula

P = VI, here p denotes power, v denotes voltage and i denotes current.

P = 5*0.5

P = 2.5 W

Energy consumed by the bulb is calculated as the product of power consumed and time.

E = Pt, where e denotes energy consumed, p denotes power and t denotes time.

E = 2.5*2.5

E = 6.25 Wh = 6.25*10^-3 kWh

Hence, energy consumed in hours will be - 6.25*10^-3 kWh