Question

Twenty lamps each of 60 watts are used each for 4 hours per day in a building. Calculate
(i) the current drawn when all the lamps are working
(ii) the monthly electricity charge at 55 paise per unit.
Assume a supply of 240V.

Answer 1

Answer:

Given:-

Power= 60 Watt

Everyday Use = 10 Hours

Total Days= 30

Cost Of elctricity per unit= 3.50 Rs.

Find:-

Total amount to be paid in 30 days

Given:-

The days can be calculated in total hours used in 30 days

Hence, Days x Everyday Use = 30 x 10 = 300 Hours

Convert, 60 Watt into Kwatt = 60/1000

By Formula,

Unit= Kwatt x Time (in hours)

U= 60/1000 x 300

U= 18

Hence, total unit used is 18.

By Formula,

Cost= Unit x Rupees per unit

Cost= 18 x 3.50

Cost= 63 Rupees

Therefore, the amount to pay in 30 days is 63 Rupees.