An electric bulb is marked 200 V, 100 W. Calculate electrical resistan

1.	An electric bulb is marked 200 V, 100 W. Calculate electrical resistance of its filament. If five such bulbs are connected in series to a 200 V supply, how much current will flow through them ?
Answer» Given P = 100 W, V = 220 V = 220 V, R = ?, I = ? R = \(\frac{V^2}{P}\) = \(\frac{(200)^2}{100}\) = 400 Ω When five are connected in series then R_net = 5 x 400 = 2000 Ω Hence current in the circuit I = \(\frac{V}{R_{net}}\) \(\frac{200}{2000}\) = 0.1 A

An electric bulb is marked 200 V, 100 W. Calculate electrical resistance of its filament. If five such bulbs are connected in series to a 200 V supply, how much current will flow through them ?

Answer»

Given P = 100 W, V = 220 V = 220 V, R = ?, I = ?

R = \(\frac{V^2}{P}\) = \(\frac{(200)^2}{100}\) = 400 Ω

When five are connected in series then R_net = 5 x 400 = 2000 Ω

Hence current in the circuit

I = \(\frac{V}{R_{net}}\) \(\frac{200}{2000}\) = 0.1 A