Question

a 2 kw heater a 200w tv and three 100 w lamps are all switched on from 6pm to 10 pm what is the total cost at rs 5.50 per kwh

Answer 1

Energy Consumption = 2(4) + 0.2(4) + 3(0.1)(4)
= 8 + 0.8 + 1.2 = 10kWh
Cost = Rs. 5.50* 10 = Rs. 55

Answer 2

Answer:

The total cost is Rs.55.

Explanation:

Here total power used, p = 2 kW + 200 W + 3 x 100W  

p = 2000 W + 200 W + 300 W = 2500 W = 2.5 kW  

All the mentioned equipment’s are switched on from 6 to 10 pm i.e. for 4 hours.

So t = 4 h

As per the formula of energy, E = p x t = 2.5 x 4 = 10 kWh

Hence total cost at Rs. 5.50 per kWh = 10 x 5.50  = 55 Rs.