CSS - PMS - CCE - PCS - General Science
Electricity & Magnetism - Conductors & Insulators
What is a semiconductor?
A. A mechanical switch only
B. A perfect conductor
C. A material whose electrical conductivity lies between that of conductors and insulators and can be controlled
D. A perfect insulator always
Correct Answer: C
Semiconductors such as silicon have controllable conductivity and underpin electronics.
CSS - PMS - CCE - PCS - General Science
Electricity & Magnetism - Conductors & Insulators
What is the main function of an insulator around a wire?
A. To generate electricity
B. To increase current without limit
C. To store data
D. To reduce unwanted current flow and protect users from electric shock
Correct Answer: D
Insulation confines current to the conducting core and improves safety.
CSS - PMS - CCE - PCS - General Science
Electricity & Magnetism - Conductors & Insulators
Why are metals generally good conductors?
A. They contain delocalized electrons that can move through the lattice
B. They have no resistance
C. They contain no protons
D. They are always magnetic
Correct Answer: A
Mobile conduction electrons carry charge through metals.
CSS - PMS - CCE - PCS - General Science
Electricity & Magnetism - Conductors & Insulators
Which material is commonly used as an electrical insulator?
A. Copper
B. Aluminum
C. Rubber
D. Silver
Correct Answer: C
Rubber has very few mobile charge carriers under ordinary conditions.
CSS - PMS - CCE - PCS - General Science
Electricity & Magnetism - Conductors & Insulators
Which material is a good electrical conductor?
A. Rubber
B. Glass
C. Dry wood
D. Copper
Correct Answer: D
Copper has many mobile electrons and low resistivity.
CSS - PMS - CCE - PCS - General Science
Electricity & Magnetism - Conductors & Insulators
What is an electrical conductor?
A. A material that allows electric charge to move relatively easily
B. A substance with no atoms
C. A material that blocks all heat only
D. A material that never contains electrons
Correct Answer: A
Conductors contain mobile charge carriers, such as electrons in metals.