An electric lamp of 100 volt,a rooster of resistance 50 volt,and a water filter of resistance 500 volt are connected in parallel to a 220 source what is the resistance of an electric iron conneded to the same source that takes as much current as all three appliances and what is the current through it?
Answers
Answer:
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
To find
(1) Resistance of an electric iron
(2) The flow of electric current through the electric iron.
The three resistors are connected in parallel as shown in the below figure.
Resistance 100 ohm, 50 ohm , 500 ohm connected in parallel
(1) Total resistance (R) can be calculated as shown below.
1/R = 1/R₁ + 1/R₂ + 1/R₃
1/R = 1/100 + 1/50 + 1/500
1/R = ( 5 + 10 + 1 )/500
1/R = 16/500
500/16 = R
Total Resistance (R) = 500/16 Ω
R = 31.25 Ω
(2) According to ohm’s law the current through a conductor between two points is directly proportional to the voltage across the two points.
V ∝ I or V = IR
R is constant called resistance.
R = V/I
500/16 = 220/I
I = 220 × (16/500)
I = 7.04 A
Therefore, the resistance of the electric iron is 31.25 Ω and the current flowing through it is 7.04 A.