ASVAB (Armed Services Vocational Aptitude Battery)Electronics Information (EI)Medium
A series circuit contains three resistors with values of 10 Ω, 20 Ω, and 30 Ω. If a 120 V power supply is connected to this circuit, what is the total current flowing through the circuit?
- A36 A
- B2 A
- C6 A
- D12 A
Show answer & explanationAnswer & explanation
Correct answer: B. 2 A
In a series circuit, total resistance (R_total) is the sum of individual resistances: R_total = 10Ω + 20Ω + 30Ω = 60Ω. Using Ohm's Law (I = V/R), the total current is I = 120V / 60Ω = 2A.
Why the other options are wrong
- A. This would result from 120V / (10Ω/3) or similar miscalculation; incorrect.
- C. This would result from 120V / 20Ω (average resistance), which is incorrect.
- D. This would result from 120V / 10Ω (smallest resistance), which is incorrect for total current.
Series Circuit
A circuit in which components are connected end-to-end, forming a single path for current flow.
- Current is the same through all components.
- Total resistance is the sum of individual resistances (R_total = R1 + R2 + ...).
- Total voltage is the sum of individual voltage drops (V_total = V1 + V2 + ...).
Memory trick: Series: Same Current, Summed Resistance, Split Voltage.