Question

an electric lamp of 100ohm a toaster of resistance 50ohm and a water filter of resistance 500ohm are connected in parallel to a 220 V source. what is the resistance of an electric iron connected to the same source that takes as much current as all three appliances, and what is current through it

Answer 1

Solution:

Resistance of electric lamp (R1) = 100 Ω

Resistance of toaster (R2) = 50 Ω

Resistance of water filter (R3) = 500 Ω

Potential difference of the source, V = 220 V






Therefore, the resistance of the electric iron is 31.25 Ω and the current flowing through it is 7.04 A.

Answer 2

In a parallel arrangement, the potential difference remain same but electric current is different.

Here, we have R₁ = 100 Ω, R₂ = 50 Ω and R₃ = 500 Ω

Total 1/R = 1/R₁ + 1/R₂ + 1/R₃

Total 1/R = 1/100 Ω + 1/50 Ω + 1/500 Ω

Total 1/R = ( 5 + 10 + 1 )/500

Total 1/R = 16/500

500/16 = Total R

Total Resistance = 500/16 Ω

Since, R = V/i

500/16 = 220/i

i = 220 × 16/500

i = 7.04 A

Here resistance and electric current used will be same.and therefore answers are :-

[1] 500/16 Ω OR

In Decimal, 31.25 Ω

[2] 7.04 A