How is resistance defined?

How is resistance defined?

• A. Energy stored in a magnetic field
• B. Opposition to current flow
• C. Amount of current
• D. Power delivered to a load

Answer: (B)

Resistance is the property of a conductor or component that opposes the flow of electric current. It sets how much current will flow for a given voltage, described by Ohm's law: V = I × R. If the voltage is fixed and resistance goes up, the current goes down; if resistance is fixed and voltage goes up, the current goes up. Resistance is measured in ohms and depends on factors like the material, temperature, length, and cross-sectional area. For example, a long, thin wire offers more opposition than a short, thick one, and many materials change their resistance with temperature. Energy stored in a magnetic field describes magnetic energy, not opposition to current. The amount of current is the flow itself, not the property that resists it. Power delivered to a load is about energy transfer rate (P = VI or P = I^2R), which depends on both voltage and current, not the resistance by itself.

Resistance is the property of a conductor or component that opposes the flow of electric current. It sets how much current will flow for a given voltage, described by Ohm's law: V = I × R. If the voltage is fixed and resistance goes up, the current goes down; if resistance is fixed and voltage goes up, the current goes up. Resistance is measured in ohms and depends on factors like the material, temperature, length, and cross-sectional area. For example, a long, thin wire offers more opposition than a short, thick one, and many materials change their resistance with temperature.

Energy stored in a magnetic field describes magnetic energy, not opposition to current. The amount of current is the flow itself, not the property that resists it. Power delivered to a load is about energy transfer rate (P = VI or P = I^2R), which depends on both voltage and current, not the resistance by itself.