Consider the given circuit and find the current flowing in the circuit and potential difference across the 15 Ω resistor when the circuit is closed.
Total resistance of the circuit
R = R1 + R2 + R3 = 5 + 10 + 15 = 30 ohm
Potential difference across the circuit using By ohm’s law
V = IR
I = V/R
I = 30 V / 30 Ω = 1 A
Potential difference across 15 ohm resistor = 1 A × 15 ohm = 15 volt