Which property is the opposition to the flow of electric current in a material?

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

Answer: (B)

Opposition to the flow of electric current in a material is called resistance. It happens because moving electrons collide with atoms and imperfections in the material, turning some of the electrical energy into heat. The more collisions there are, the higher the resistance. Temperature affects this too—heating a conductor usually increases its resistance. For a given material at a fixed temperature, resistance depends on length and cross-sectional area: longer wires resist more, while thicker wires resist less. Ohm’s law ties it all together: current equals voltage divided by resistance (I = V/R). So, for a given voltage, larger resistance means smaller current. The other terms describe different ideas—voltage is the driving push, capacitance relates to storing charge, and inductance resists changes in current—so they aren’t the steady opposition to flow that resistance represents.