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Question
In the circuit diagram given below, three resistors R1, R2, and R3 of 5 Ω, 10 Ω and 30 Ω, respectively are connected as shown
Calculate:
- current through each resistor.
- total current in the circuit.
- total resistance in the circuit.
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Solution
a. Let I1, I2 and I3 be the current flowing through the resistors of 5 Ω, 10 Ω and 30 Ω, respectively.
According to Ohm's law, V = IR
Here, V = 12 V and R = 5 Ω
`I = V/R`
`I_1 = 12/5 = 2.4 A`
`I_2 = 12/10 = 1.2 A`
`I_3 = 12/30 = 0.4 A`
b. Total current through the circuit, I = I1 + I2 + I3
= 2.4 A + 1.2 A + 0.4 A
= 4 A
c. The resistors of 5 Ω, 10 Ω and 30 Ω are connected in parallel. Therefore, the net resistance will be:
`1/ R = 1/R_1 + 1/R_2 + 1/R_3`
`1/R = (1/5) + (1/10) + (1/30)`
`1/R = (6 + 3 +1)/30`
`I/R = 10/30`
R = 3 Ω
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