These Conductors and Insulators Question and Answers are most important for your upcoming IIT-JEE/JEE-Mains exams as well as GATE and various other engineering examinations. These selective Conductors and Insulators Question and Answers are often asked in various board exams also.
Conductors and Insulators Question and Answers
1. The rubber used in the wheels of aero-plane is _________
a) Perfect insulator
b) Slightly conducting
c) Can be an insulator or conducting
Explanation: Due to high friction during takeoff, a huge amount of charge is produced on the rubber of the wheel of a plane. This charge must be sent to the ground. So, the rubber used is slightly conducting, else the huge charge produced may produce a spark and can cause an accident.
2. Current carrier in conductors is ____
Explanation: Conductors have lots of free electrons that can carry electricity if the potential difference is applied across them. Protons are positively charged particle and Neutron are electrically neutral. They don’t carry electricity in conductors.
3. Which group among the following is insulator?
a) Silver, copper, gold
b) Paper, glass, cotton
c) The human body, wood, iron
d) Glass, copper, paper
Explanation: Glass, paper, and cotton are good quality insulators. The rest options contain one or more conducting materials. Silver is the best conductor material available in nature. But it is costly, so it can’t be used in the electricity distribution system.
4. The band gap between the valence band and conduction band is the measure of ______
a) The conductivity of the material
b) The resistivity of the material
c) Charge density
d) Ease of ionization
Explanation: The more the band gap between the valence band and conduction band, the worse is the conductivity of the material. For conductors, there are overlapping bands. So, conductors can carry electricity. But there is a huge energy gap in the case of insulators. So, they don’t carry electricity at all.
5. Insulation breakdown may occur at _______
a) High temperature
b) Low temperature
c) At any temperature
d) Depends on pressure
Explanation: At high temperatures, electrons of insulators get excited and then the electrons can overcome the large energy band gaps between valence and conduction bands. So a large number of electrons travel to the conduction band and they act as conductor i.e. insulation breakdown occurs.
6. Superconductors have __________
a) Almost zero resistivity
b) Very high resistivity
c) Temperature-dependent resistivity
d) Moderate value of resistivity
Explanation: Semiconductors are those which carry current with almost zero resistivity at a very low temperature (example: Lead at -272-degree centigrade). So, they have a very huge amount of current flow through them.