a) Three resistors 1 Ω, 2Ω, and 3 Ω are combined in series. What is the total resistance of the combination?
b) If the combination is connected to a battery of EMF 12 V and negligible internal resistance, obtain the potential drop across each resistor.

Solution

Given, three resistors of resistances 1

Ω, 2 Ω and 3 Ω

combined in series.

Therefore,
a) Total resistance of series combination is given by,

R = R_{1} + R_{2} + R_{3} = 1 + 2 + 3 = 6 Ω

b) If the combination is connected to a battery of 12 V and negligible internal resistance.

Current through the circuit,

I = \frac{E}{R + r} = \frac{12}{6 + 0} = 2 A

Potential drop across R₁ = 2 x 1 V = 2 V
Potential drop across R₂ = 2 x 2 V = 4 V
Potential drop across R₃ = 2 x 3 V = 6V

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