Answer:
0.6 A
Explanation:
When resistors are connected in parallel,
(i) The voltage across each of the resistor is the same
(ii) The current in the circuit is equal to the sum of the current flowing through the individual resistor.
Firstly, we look for the voltage across the the R₃ resistor.
From Ohm's law,
V₃ = I₃R₃................. Equation 1
Where V₃ = Voltage across R₃, I₃ = current flowing through R₃
Given: I₃ = 200 mA = 0.2 A, R₃ = 90 Ω
Substitute into equation 1
V₃ = 0.2(90) = 18 V.
Note: V₁ = V₃ = 18 V.
Secondly, we calculate the current flowing through R₁
Using,
I₁ = V₁/R₁........................... Equation 2
Given: V₁ = 18 V, R₁ = 30 Ω
Substitute these values into equation 2
I₁ = 18/30
I₁ = 0.6 A
