GED Science TestPhysical ScienceEasy
An electrical engineer is designing a circuit. They need to select a material that offers very high resistance to the flow of electric current. Which of the following materials would be most suitable for this purpose?
- ARubber insulation
- BCopper wire
- CSilver contact
- DAluminum foil
Show answer & explanationAnswer & explanation
Correct answer: A. Rubber insulation
Materials that offer very high resistance to the flow of electric current are called insulators. Rubber is an excellent electrical insulator, commonly used to protect wires and components from current leakage. Copper, aluminum, and silver are all good conductors with low resistance.
Why the other options are wrong
- B. Copper is a good electrical conductor, meaning it has low resistance.
- C. Silver is one of the best electrical conductors, having very low resistance.
- D. Aluminum is also a good electrical conductor, though less efficient than copper.
Electrical Insulator
An electrical insulator is a material whose internal electric charges do not flow freely, making it very difficult to conduct an electric current under the influence of an electric field.
- High electrical resistance
- Prevents the flow of electricity
- Examples: rubber, glass, plastic, ceramic
Memory trick: Conductors let current cruise, Insulators obstruct its use.