Question

In a house two 60 w electric bulbs are lighted for 4 hour and three 100 w bulbs for 5hrs everyday calculate the electric energy cnsumed in 30 days

Answer 1

Energy consumed by the first bulb:
$E_{1}=Pt=(2*60)*(30*4*60*60)=51840000J$
Energy consumed by the second bulb:
$E_{2}=(3*100)*(30*5*60*60)=162000000J$
so the total energy consumed:
$E=E_{1}+E_{2}=213840000J=45014.4 KW-h$