ARRL Technician Practice Exam

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Prepare for the ARRL Technician Exam. Study with flashcards and multiple choice questions, each question has hints and explanations. Get ready for your exam!

Each practice test/flash card set has 50 randomly selected questions from a bank of over 500. You'll get a new set of questions each time!

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What formula is used to calculate resistance in a circuit?

Voltage (E) divided by current (I)
Current (I) divided by voltage (E)
Voltage (E) multiplied by current (I)
Resistance (R) multiplied by voltage (E)

The correct answer is: Voltage (E) divided by current (I)

The correct formula to calculate resistance in a circuit is given by the relationship defined by Ohm's Law, which states that resistance (R) is equal to the voltage (E) across the circuit divided by the current (I) flowing through it. This is mathematically expressed as R = E / I. In practical terms, this means that if you know the voltage applied across a circuit and the current that is flowing through it, you can easily calculate the total resistance in that circuit. This formula is essential for understanding how electrical components operate together in any circuit and is a foundational concept in electronics. The other choices do not accurately represent the relationship between voltage, current, and resistance according to Ohm's Law. Some represent the relationships of current and voltage in ways that do not conform to the established principles of electrical theory, making them inappropriate for determining resistance directly.