What unit measures electrical resistance?

The correct answer is Ohm, which is the unit specifically designated for measuring electrical resistance. In the context of electrical circuits, resistance is a measure of how much a material opposes the flow of electric current. The concept of resistance is essential for understanding how electricity behaves in various materials and circuits.

Ohm's Law, which states that voltage equals current times resistance (V = I × R), highlights the direct relationship between voltage, current, and resistance. This law lays the foundation for analyzing and designing electrical systems. In practical applications, knowing the resistance in a circuit helps determine how much current will flow when a certain voltage is applied, which is vital information in various electrolysis processes.

The other units mentioned are related to electrical concepts but do not measure resistance. A watt is a unit of power, quantifying the rate of energy transfer. A volt measures electric potential or voltage, indicating the energy per unit charge. An ampere is a unit of electric current, representing the flow of electric charge. Understanding these distinctions is crucial for correctly applying the concepts of electricity and electrolysis in practice.