Four light bulbs are connected in series to a 6.0 V battery. Each bulb has a resistance of 10 Ω. Calculate the total current through the circuit.

Four light bulbs are connected in series to a 6.0 V battery. Each bulb has a resistance of 10 Ω. Calculate the total current through the circuit.

• A. 0.15 A
• B. 0.015 A
• C. 1.5 A
• D. 6 A

Answer: (A)

In a series circuit, the same current flows through every component, and the resistances add up to give the total resistance. Four bulbs at 10 Ω each give a total resistance of 40 Ω. With a 6.0 V battery, the current is I = V / R = 6.0 V / 40 Ω = 0.15 A. That current goes through each bulb in the series. The other numerical options would require different total resistance or a different voltage. So the current in the circuit is 0.15 A.

In a series circuit, the same current flows through every component, and the resistances add up to give the total resistance. Four bulbs at 10 Ω each give a total resistance of 40 Ω. With a 6.0 V battery, the current is I = V / R = 6.0 V / 40 Ω = 0.15 A. That current goes through each bulb in the series. The other numerical options would require different total resistance or a different voltage. So the current in the circuit is 0.15 A.