Question

A room has two tube lights, a fan and a TV. Each tube light draws 40 W, the fan draws 80 W, and the TV draws 60 W. On the average, the tube lights are kept on for five hours, the fan for twelve hours and the TV for eight hours every day. The rate for electrical energy is Rs 3.10 per kWh. Calculate the cost of electricity used in this room in a 30-day month. kW.​

Answer 1

Rate of electrical energy used per hour(tube light)=3.10*40=₹120
Rate of electrical energy used per day( tube light)= 120*5=₹620
Rate of electrical energy used per 30 days ( tube light )= 620*30= 18,600


OMG I think I did wrong sorry

Answer 2

For each tube light, power,

P = 40/1000 W

So, the energy consumed by the fan in a day is

➲ u = P x t

➲ u = (40/1000)kW x (5)h

➲ u = 200/1000

➲ u = 0.2kWh

Energy consumed by the fan in a day is

➲ u = P x t

➲ u = (80)W x (12)h

➲ u = (80 W)x(12 h)

➲u = 960/1000

➲u = 0.96 kWh.

Total energy consumed by TV in a day is

➲ u = P x t

➲ u = (60)W x (8)h

➲ u = 480/1000

➲ u = 0.48kWh

Total energy consumed in a day

➲ 2 x 0.2 kWh + 0.96 kWh + 048 kWh

➲ 1.84 kWh

Energy consumed in a month is

➲ (1.84 kWh) x 30

➲ 55.2 kWh.

The cost of electricity-

➲ Rs (55.2 x 3.1)

➲ Rs 171.12

Therefore:-

The cost of electricity used in the month is 171.12 rupees.