Question

Two lamps, One rated 100W at 220V and the other 200V are connected in series and in parallel to electric main supply of 220V, find the current drawn in each case.

Answer 1

For lamp 1 Voltage=220v Power=100w By ohms law P=VI I=p/v I=100/220 I= 0.45 For lamp 2 Voltage =220v Power=200 w P=vI I=p/v L I=200/220 I = 0.9

Answer 2

Answer:

I_series = 0.30 A

I_parallel = 1.36 A

Explanation:

Given :

Two lamps power as 100 W and 200 W at 220 V.

We have resistance formula :

R₁ = 220 × 220 / 100 = 484 Ω

R₂ = 220 × 220 / 200 = 242 Ω

In series combination :

R_net = 484 + 242 Ω

= > 726 Ω

We have ohm's law :

V = I R

I = 220 / 726 A

I = 0.30 A

( ii ) In parallel combination :

1 / R_net = 1 / 484 + 1 / 242 Ω

R_net = 484 / 3 Ω

Given :  V = 220 V

I' = 220 / 484 × 3 A

I' = 1.36 A