Question

An electric bulb is rated 220v - 100 what is the resistance if 5bulbs are burn for 4hoirs

Answer 1

220÷100=2.2
2.2×5×4=44

Answer 2

Rating of bulb = 220 v - 100 A .

Potential difference = 200 v

Current = 100 A

Power = 100 A × 220 V

           = 22000 W.

I²Rt = 22,000 W × t

= > I²R = 22,000 W

= > 100² × R = 22,000 W

= > R = 22,000 ohms/ ( 100 × 100 )

= > R = 22,000 / 10,000

= > R = 22/10

= > R = 2.2

The resistance is 2.2 ohms