Energy Band Structure and Superconductors

Which of the following correctly describes the energy band structure of conductors?

• A) Valence band and conduction band overlap

• B) There is a wide energy gap between valence and conduction band

• C) There is a small energy gap between valence and conduction band

• D) Conduction band is completely filled

Which of the following substances typically have a very small energy gap (about 1 eV)?

• A) Conductors

• B) Semiconductors

• C) Insulators

• D) Superconductors

Which of the following materials has a very large energy gap (greater than 3 eV), making it a poor conductor of electricity?

• A) Silver

• B) Silicon

• C) Rubber

• D) Germanium

What happens to the resistivity of a metallic conductor as temperature increases?

• A) It increases

• B) It decreases

• C) It remains constant

• D) It first decreases then increases

The resistivity of a semiconductor __________ with an increase in temperature.

• A) Increases

• B) Decreases

• C) Remains the same

• D) Becomes infinite

A thermistor typically shows which type of temperature coefficient of resistance?

• A) Positive temperature coefficient

• B) Negative temperature coefficient

• C) Zero temperature coefficient

• D) Infinite temperature coefficient

Which of the following statements is TRUE for superconductors?

• A) They have infinite resistance below critical temperature

• B) They have zero resistance below critical temperature

• C) They have high resistance at all temperatures

• D) Their resistance increases with decrease in temperature

Which of the following is a potential application of Room Temperature Superconductors (RTS)?

• A) Lossless power transmission

• B) Heating elements

• C) High-resistance circuits

• D) Conventional incandescent bulbs

Superconductors can be used to create:

• A) Magnetic levitation trains

• B) Ordinary house wiring

• C) High resistance switches

• D) Standard electrical heaters

One major advantage of room temperature superconductors is:

• A) High energy consumption

• B) Need for cooling with liquid nitrogen

• C) Elimination of energy losses in power cables

• D) Increased resistance with heat