Question

Coil of heater connected to a 200 volt line consumes a power of hundred watt . the coil is divided into two equal parts the two parts are combined in parallel and connected to a 200 volt line what will be the power consumed by the new combination

Answer 1

Power rating,m P = 100 W

voltage supply, V = 200V

thus resistance of the coil:

P = V^2 / R

thus R = 40000/100
= 400 ohm

hence of the two new parts produced, new resistance of each part, R' = 200 ohm each

on parallel connection, net resistance:

1/Rt = 1/R' + 1/R'

hence Rt = R'/2 = 100 ohm

and the new power rating
P = V^2 /Rt
= 40000/100
= 400 W