Question

Several electric bulbs designed to be used on a 220 V electric supply line, are rated 10 W. How many lamps can be connected in parallel with each other across the two wires of 220 V line if the maximum allowable current is 5 A?

Answer 1

Resistance R₁ of the bulb is given by the expression,

Where,

Supply voltage, V = 220 V

Maximum allowable current, I = 5 A

Rating of an electric bulb

According to Ohm’s law,

V = I R

Where,

R is the total resistance of the circuit for x number of electric bulbs

Resistance of each electric bulb, Ω

Therefore, 110 electric bulbs are connected in parallel.