### Q.12:- 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:-**

Resistance

*R*_{1}of the bulb is given by the expression,Supply voltage,

*V*= 220 VMaximum allowable current,

*I*= 5 ARating of an electric bulb P=10watts

Because R=V

^{2}/PAccording 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, R

_{1}=4840Ω∴ Number of electric bulbs connected in parallel are 110.