Question

Three electric bulbs of rating 60 W each are joined in series and then connected to electric
mains. The power consumed by these three
bulbs will be​

Answer 1

Let resistance of each bulb is R

then total resistance of 3 bulbs=3R

power=V2/R =60W for each bulb

when three bulbs connected in series then power=

V2/(3R)

=(1/3)(V2/R)

=(1/3)(60)

=60/3 =20 W

(voltage is same when one bulb is used or three used.

hope it helps you!!!!!!!