Question

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

Answer 1

Explanation:

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.