Question

-There are five electric appliances, viz. electric heater and electric lamp, an electric fan, computer and an exhaust fan are connected in parallel in a household. The resistance electric appliances are 40Ω, 5 Ω, 8Ω, 20Ω and 10Ω respectively. If an electric current of 240V is flowing through the circuit then find Total electric current (I) through the circuit. *

Answer 1

Explanation:

Let the resistances be R1=40Ω, R2=5Ω, R3=8Ω R4=20Ω, R5=10Ω.

As the resistances are connected in parallel,

1/Rp= 1/R1 + 1/R2 + 1/R3 + 1/R4 + 1/R5

=> 1/Rp= 1/40+1/5+1/8+1/20+1/10

=>1/Rp= 1+8+5+2+4/40

=>1/Rp= 20/40

=>Rp=2

∴Effective resistance= 2Ω

We know,

V=IR (Ohm's Law)

=>240= I×2

=>I= 120

∴Total current (I)= 120A