Question

Q1. An electric bulb has power rating of 220V -100W . Calculate the resistance of the bulb and also

maximum current that the bulb can withstand .​

Answer 1

Answer:

Explanation:

As per the equation P = V2/R

we have If V = 220 V

100 W = 2202/R

R = 2202/100 Ω = 484 Ω. This is the resistance of the bulb.

When V = 110 V, power consumed = V2/R = 1102/484 = 25 W.

So, 25 W power is consumed when it is operated on 110 V.

Answer 2

Answer:

Solution

(a) Total resistance of the circuit =R

1

+R

2

=20+4=24ohm

(b) We know that

V=IR

Therefore,

6=I×24

I=6/24=0.25amp

(c) p.d. across bulb =IR

1

=0.25×20=5V

(d) p.d. across resistance wire =IR

2

=0.25×4=1V

=0.25×4=1V