247SimpleTests
ASVAB · Circuits and Ohm's Law

Using Ohm's law, if a circuit has 12 volts and a resistance of 4 ohms, what is the current?

Reviewed by Jordan Morley, Editorial Lead at 247SimpleTests. Written by the 247SimpleTests Editorial Team from the official source material cited on every question.

Correct answer

3 amps

  1. A 48 amps
  2. B 3 amps
  3. C 0.33 amps
  4. D 8 amps

Why this is the answer

Ohm's law states V = I × R, where V is voltage, I is current, and R is resistance. To find current, rearrange to I = V ÷ R. Here I = 12 volts ÷ 4 ohms = 3 amps. Ohm's law is the single most important relationship in basic electronics, and you should be able to solve for any of the three variables: V = IR, I = V/R, and R = V/I. A common error is multiplying instead of dividing (12 × 4 = 48). The current in this circuit is 3 amperes.
Source: ASVAB Electronics Information — Ohm's Law

Practice more questions

This question is from our ASVAB Practice Tests practice test. Take the full practice test to test your knowledge across all Circuits and Ohm's Law and other topics.

Take the Electronics Information practice test →

About this topic: Circuits and Ohm's Law

Circuits and Ohm's Law questions ask you to calculate voltage, current, resistance or power, and to understand series versus parallel circuits — how resistance adds in series and reduces in parallel, and what happens when one component fails. This is one of 17 Electronics Information questions on circuits and ohm's law, each with a full explanation on a single study page.

New to this exam? Our ASVAB exam guide explains the format, scoring, and how to prepare.

Related questions

Circuits and Ohm's Law

Using Ohm's Law, if a circuit has 12 volts and 4 ohms of resistance, what is the current?

 Circuits and Ohm's Law

Three resistors of 10Ω, 20Ω, and 30Ω are connected in series. What is the total resistance?

 Circuits and Ohm's Law

What does a fuse do in a circuit?

 Circuits and Ohm's Law

Which of the following circuits has the same current flowing through all components?

Recommended study materials

Study guide

ASVAB Total Prep (Kaplan)

Kaplan's complete ASVAB guide with 1,000+ practice questions, 6 full-length tests, and AFQT focus.

Check Price → Study guide

Barron's ASVAB with Online Tests 12th Ed.

Comprehensive ASVAB review for all nine subtests with full-length practice exams and online tools.

Check Price → Study guide

ASVAB for Dummies 4th Ed. (Wiley)

Accessible, thorough ASVAB prep covering all subtests with tips for boosting your AFQT score.

Check Price →

As an Amazon Associate, CJ Affiliate, and AWIN publisher we earn from qualifying purchases. Links above are affiliate links. Full disclosure →