Which one of the following is a measure of a material's opposition to the flow of electric current?

The measure of a material's opposition to the flow of electric current is known as resistance, and it is quantified in Ohms. This concept is fundamental in understanding how electrical circuits function, as resistance affects how easily current can flow through materials. The formula that ties together voltage (volts), current (amperes), and resistance (ohms) is Ohm's Law, which states that Voltage = Current × Resistance.

Volt is a unit of electric potential, while watt is a measure of electrical power. Ampere quantifies the flow of electric current itself. Thus, while each of these terms plays a critical role in understanding electricity, Ohm is the specific term that denotes resistance, making it the correct choice in the context of opposition to current flow. Understanding these distinctions is crucial for anyone working with electrical systems, especially in wastewater treatment applications where electrical equipment is commonly used.