Question

A bulb is rted 200v, 40w what is resistance , 5 bulbs are lighted for 5 hrs calculate energy consumed, find cost if the rate is 5.10per kWh

Answer 1

Power=potential difference*power
40=200*I
I=200/40=5 ampere
Resistance(R)=V/I
R=200/5=40 ohm
5 hours=5*60 min =300*60=18000sec
Energy=power*time
=40*18000
=720000J