Question

several electrical bulbs designed to be used a220V electric supply line rated at 10W .howvmany lamps can be connected in parallel with each otherbacross the two wires of 220V lines if the maximum allowed current is 5A

Answer 1

Resistance R1 of the bulb is given by the expression,
Supply voltage, V = 220 V
Maximum allowable current, I = 5 A
Rating of an electric bulb P=10watts
Because R=V2/P


According to Ohm’s law,
V = I R
Let R is the total resistance of the circuit for x number of electric bulbs
R=V/I
=220/5=44 Ω
Resistance of each electric bulb, R1=4840Ω

∴ Number of electric bulbs connected in parallel are 110.

Answer 2

Is it wrong?

Taking No. Of bulbs = x

P=10 watt

V=220 volts

I=5 ampere

xP=VI

x=220•5/10

x=22•5

x=110 bulbs.