In physics, which quantity is defined as the resistance to the flow of electric current?

In physics, which quantity is defined as the resistance to the flow of electric current?

• A. Voltage
• B. Current
• C. Resistance
• D. Capacitance

Answer: (C)

Resistance is the opposition to the flow of electric current. It tells you how hard it is for charges to move through a material or device. The relationship called Ohm's law, V = IR, connects the voltage (the driving push), the current (the rate of flow), and the resistance (the opposition). For a given voltage, a higher resistance yields a smaller current; the unit of resistance is the ohm (Ω), defined as one volt per ampere. Resistance depends on material, temperature, length, and cross-sectional area: a longer, thinner, or hotter conductor typically has higher resistance. In contrast, voltage is the potential difference that drives current, current is the amount of charge flowing per second, and capacitance measures how much charge a component can store per volt. Thus the quantity that matches the definition of opposition to current flow is resistance.

Resistance is the opposition to the flow of electric current. It tells you how hard it is for charges to move through a material or device. The relationship called Ohm's law, V = IR, connects the voltage (the driving push), the current (the rate of flow), and the resistance (the opposition). For a given voltage, a higher resistance yields a smaller current; the unit of resistance is the ohm (Ω), defined as one volt per ampere. Resistance depends on material, temperature, length, and cross-sectional area: a longer, thinner, or hotter conductor typically has higher resistance. In contrast, voltage is the potential difference that drives current, current is the amount of charge flowing per second, and capacitance measures how much charge a component can store per volt. Thus the quantity that matches the definition of opposition to current flow is resistance.