Question

A domestic circuit has 5A fuse . How many bulbs of rating 100W ,220V can be safely used in times

Answer 1

Suppose x number of such bulbs can be used. Power of one bulb =100 watt Power of x bulbs (p)= 100 × x watts Potential difference (V) =220 volts I=5 A We know that P= V I 100x =200 ×5 x = 11 bulbs.

Answer 2

let no.of bulbs be X where I=5A      Resistance = 220V      Power  =  100W * X

As,     
         P=VI
          100W * X = 5A * 220V
            X = 5*220/100
            THEREFORE           
                                               X = 11 Bulbs