Question

two lamps one rated 100W;220V and the other 60W;220V,are connected in parallel to electric mains supply. find the current drawn by the two bulbs from the line , if the supply voltage is 220V

Answer 1

P.D = 220V

For first lamp

P = VI

100 = 220 × I

I = 100 / 220

I = 5/11 A


For second lamp

P = VI

60 = 220 × I

I = 60 / 220

I = 3 / 11A

HOPE IT IS MOST HELPFUL!!!!!

Answer 2

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Given that :

✠ There are two lamps that are connected in parallel to the electric main supply.

✠ One of the lamp rated as 100 W ; 220 V

Means,

R₁ = 220² / 100

✠ The another lamp rated 60 W ; 220 V

Means,

R₂ = 220²/60

To find :

✠ Current

Solution :

✠ Total current = 0.73 A

Using concept :

✰ Resistance (parallel connection).

✰ Ohm's law

Using formula -

✰ Resistance (parallel connection) = 1/R = 1/R₁ + 1/R₂ .... 1/Rn

✰ Ohm's law => V = IR

Where,

★ I denotes total current

★ R denotes resistance

Final solution :

~ Now,

➝ 1/R = 1/R₁ + 1/R₂ .... 1/Rn

➝ (1/220² / 100) + (1/220² / 60)

Cancelling the digits,

➝ R = 220² / 60

~ Using ohm's law

➝ V = IR

➝ V = 220²/106 I

➝ V = 48400/160 I

➝ 200 = 48400/160 I

➝ 200 = 4840/16 I

Cancelling the digits

➝ 200 = 605/2 I

➝ 200 = 302.5 I

➝ 200 / 302.5 = I

➝ 0.73 = I

➝ I = 0.73 A

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