Question

Two lamps,one rated 100W at 220v and the other 200w at 220v are connected
1. In series and
2. In parallel to electric main supply of 220v. Find the current drawn in each case.

Answer 1

Here is ur answer.......

Hope it helps!!

☺☺

Answer 2

Given:

Lamp 1,

Voltage = 100 w

Potential = 220 v

Lamp 2,

Voltage = 200 w

Potential = 220 v

To find:

The current

Solution:

To find resistance,

Resistance = ( Voltage )^2 / Potential

Substituting.

Resistance for lamp 1 = ( 220 )^2 / 100

Resistance for lamp 1 = 484 Ω

Resistance for lamp 2 = ( 220 )^2 / 200

Resistance for lamp 2 = 242 Ω

In a series,

Current = Voltage / Resistance

Here,

Resistance = Resistance for lamp 1 + Resistance for lamp 2

484 + 242

Resistance = 726 Ω

Hence,

Current = 220 / 726 = 0.3 Amp

In parallel,

Resistance  = Resistance for lamp 1 * Resistance for lamp 2/( Resistance for lamp 1 + Resistance for lamp 2 )

484 × 242 / ( 484 + 242 )

= 4 × 242/6

Resistance = 484/3 Ω

Current = 220 / ( 484 / 3 )

Hence,

Current = 1.36 Amp

HOPE IT HELPS..