Question

A domestic circuit has 5a fuse . How many bulbs rating 100w ,220v can be safely used in circuit

Answer 1

Current used by one bulb=V/P=220/100=2.2A
2*2.2=4.4A therrfore 2 bulbs can be used as it is less than 5A

Answer 2

Answer: 11

Explanation:

For one bulb, power drawn = 100 W.

Let there be x number of bulbs. Then power consumed by each bulb is (100 x) W.

Maximum power that can be consumed before the fuse wire melts,

P = V I ( From Joule's Heating)

P = 220 × 5 = 1100 W

⇒100 x = 1100

⇒ x = 11