Question

Two lamps, one rated 100 W at 220 v. and other 200 W at
220 V are connected (a) in series (b) in parallel
to electric main supply of 220 V Find the current
drawn in each case.

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Answer 1

Answer:

Explanation:

Firstly we find the resistance of two lamps:

$P=\frac{V^{2}}{R}$

$R=\frac{V^{2}}{P}$

Answer 2

Explanation:

Both the bulbs are connected in parallel. Therefore, potential difference across each of them will be 220 V, because no division of voltage occurs in a parallel circuit.

Current drawn by the bulb of rating 100 W is given by,Power = Voltage x Current

Current = Power/Voltage = 60/220 A

Hence, current drawn from the line = 100/220 + 60/220 = 0.727 A