Question

A student’s room has a TV (250 W) ,heater (1150 W) and lamp (200 W)
Electricity costs 10 fills per KWh.
Calculate how much it would cost to run these three appliances for a total of 2 hour 30 minutes

Answer 1

Given:-

Power consumption of TV, heater and lamp is 250,1150,200 W respectively.

total time of running these appliances, t=2 hr+30 min=2.5 hr

cost of 1 kWh=10/-

To Find:-

cost of running these appliances

Explanation:-

$\text{Total energy consumed by these appliances}=250+1150+200=1600W\\\\\text{total time of running}=2.5hr=9000 s$

$\Rightarrow \text{total energy in kJ}=\dfrac{1600\times9000}{1000}=14400kJ\\\\\text{cost of 1 kWh}=10/- \text{ and } 1kWh=3600kJ\Rightarrow 1kJ=\dfrac{10}{3600}/-\\\\\Rightarrow \text{total cost}=\dfrac{10}{3600}\times14400=40/-$