What is the current through each 100 Ω resistor in the series arrangement across 40 V?

What is the current through each 100 Ω resistor in the series arrangement across 40 V?

• A. 0.01 A
• B. 0.1 A
• C. 0.4 A
• D. 1 A

Answer: (B)

Current through each resistor in a series circuit is the same, and the total resistance is the sum of the resistors. With four 100 Ω resistors in series, the total resistance is 400 Ω. The supply is 40 V, so the current is I = V / R = 40 / 400 = 0.1 A. This same 0.1 A flows through every resistor, and each resistor drops V = I × R = 0.1 A × 100 Ω = 10 V, adding up to the 40 V supply. If the number of resistors were different, the current would change accordingly, which is why 0.1 A is the correct current for this arrangement.

Current through each resistor in a series circuit is the same, and the total resistance is the sum of the resistors. With four 100 Ω resistors in series, the total resistance is 400 Ω. The supply is 40 V, so the current is I = V / R = 40 / 400 = 0.1 A. This same 0.1 A flows through every resistor, and each resistor drops V = I × R = 0.1 A × 100 Ω = 10 V, adding up to the 40 V supply. If the number of resistors were different, the current would change accordingly, which is why 0.1 A is the correct current for this arrangement.