Thu September 12, 2013 By: Praveen Kumar

A heater coil is rated 100w, is cut into two identical parts.both parts are connected together in parallel to the same source of 200v.calculate the energy liberated per secondin the new combination.

Expert Reply
Fri September 13, 2013
power rating,m P = 100 W
voltage supply, V = 200V
thus resistance of the coil:
P = V2 / 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 = V2 /Rt = 40000/100 = 400 W
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