A circuit has a fuse of 5 A. What is the maximum number of 100 W(220 V) bulbs that can be safely...

Q. A circuit has a fuse of 5 A. What is the maximum number of 100 W (220 V) bulbs that can be safely used in the circuit ?

Solution. Suppose x bulbs can be used safely.

Now, Power of 1 bulb = 100 W

So, Power of x bulbs, P = 100 × x watts

Potential difference, V = 220 volts

Current, I = 5 amperes

Now, Power, P = V × I

So, 100 × x = 220 × 5

x = 220 × 5 / 100

x = 11

Thus, a maximum number of 11 bulbs can be used.