What formula is used to calculate resistance in a circuit?

• A. R = E / I
• B. R = I / E
• C. R = E + I
• D. R = E - I

Answer: (A)

The formula for calculating resistance in a circuit is derived from Ohm's Law, which states that voltage (E) is equal to the product of current (I) and resistance (R). This relationship can be rearranged to solve for resistance, leading to the formula R = E / I. In this formula, R represents resistance measured in ohms (Ω), E represents voltage measured in volts (V), and I represents current measured in amperes (A).

Using this formula, you can determine how much resistance is present in a circuit based on the values of voltage and current. It’s a fundamental concept in electrical engineering and the operation of circuits, applicable in various contexts, such as troubleshooting and circuit design.

The other options do not adhere to the principles of Ohm's Law. They either misrepresent the relationship between voltage, current, and resistance or create non-meaningful mathematical expressions. Understanding the correct formula is crucial for effective analysis and problem-solving in electrical circuits.