In the diagram below, a battery with an emf of 12 V and an internal resistance of 1 Ω, is
connected to three resistors with resistance R, 2R and R. A voltmeter V is connected across the
battery. The ammeter A has a negligible resistance
Diagram:
Battery (+) ----(R)----(2R)----(R)---- Battery (-)
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(+) (+) (+)
Given:
Emf of battery (ε) = 12 V
Internal resistance of battery (r) = 1 Ω
Resistances in circuit: R, 2R, R
To find the total current in the circuit:
Total resistance (R total) = r + R + 2R + R = 5R + 1
Total current (I) = ε / R total
I = 12 / (5R + 1)
To find the voltage across the voltmeter:
Voltage across voltmeter = ε - I * r
V = 12 - I * 1
To find the voltage across the resistors:
Voltage across resistors = I * R
Voltage across R = I * R
Voltage across 2R = I * 2R
Voltage across R (second one) = I * R
Hope this helps. Let me know if you need further assistance.