What unit measures resistance in electrical circuits?

• A. Amperes
• B. Volts
• C. Coulombs
• D. Ohms

Answer: (D)

Resistance in electrical circuits is measured in ohms. This unit is named after Georg Simon Ohm, who formulated Ohm's Law, which relates voltage, current, and resistance in an electrical circuit. According to Ohm's Law, the resistance of a circuit can be calculated by dividing the voltage across the circuit by the current flowing through it. Therefore, understanding resistance as a measure of how much a material opposes the flow of electric current is essential for anyone working with electrical systems.

Other units provided in the options relate to different electrical properties: amperes measure current (the flow of electric charge), volts measure electric potential (the pressure that pushes electric charges through a conductor), and coulombs measure electric charge (the quantity of electricity). Each of these units plays a critical role in electrical theory and practice, but when specifically discussing resistance, the correct unit is, indeed, ohms.