Question

a lamp consumes 500 joules of electric energy in 20 seconds what is the power of the lamp also find the electric energy consumed in units if the lamp operates for 2 hours daily for 15 days

Answer 1

Given: Energy = 500 J
            Time = 20 sec
            
 now     power = work done / time
                       = 500 / 20
                       = 25 W
                       = 25/1000
                       = 0.025 KW
now energy consumed in one day is 2 hrs
therefore       energy consumed in one day = 0.025 × 2
                                                                     = 0.05 KWH
therefore energy consumed in 15 days = 0.05 × 15
                                                              = 0.75 KWH ( units )