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The objects or substances that allow electric current to flow across them are known as conductors. They conduct electricity because electrons can easily move from atom to atom inside them. Conductors also allow heat or light to be transferred from one source to another.
Insulators are materials or substances that impede current flow or do not allow it to flow through them. They are, on the whole, substantial in nature. Insulators are also used in a wide range of systems. They don’t allow heat to travel through them. The resistivity of insulators is what distinguishes them from conductors.
1. Which of the mentioned elements is the most conductive?
a) Iron
b) Silicon
c) Silver
d) Copper
Answer: Correct option will be (c) Silver.
Reason: The electrons in this element have more freedom to travel than those in other elements.
2. Why is copper the material of choice for electrical wires?
a) Copper is an excellent electrical conductor
b) Poor electrical conductors
c) Insulators
d) Superconductors
Answer: Correct option will be: (a) Copper is an excellent electrical conductor.
3. In conductors, the current carrier is:
a) Electron
b) Proton
c) Neutron
d) Positron
Answer: Correct option will be: (a) Electron.
4. The energy gap is at its widest in
a) Conductors
b) Semi-conductors
c) Insulator
d) Superconductor
Answer: Correct option will be: (c) Insulators.
5. ____ is a kind of insulator.
a) Mica
b) Silicon
c) Copper
d) Silver
Answer: Correct option will be: (a) Mica.
Reason: Mica is unique in that it is an excellent electrical insulator and a strong thermal conductor at the same time. Block mica is most commonly used as an insulating material in electronic equipment.
6. Insulation failure can happen at:
a) high temperatures
b) low temperatures
c) any temperature
d) dependent on pressure
Answer: Correct option will be: (a) High temperatures.
Reason: At high temperatures, insulator electrons become excited, allowing them to bridge the huge energy band gaps between the valence and conduction bands. As a result, a high amount of electrons move into the conduction band and act as conductors, causing insulation breakdown.
7. The property of superconductor is that it has:
a) Nearly no resistance
b) Extremely high resistivity
c) Temperature-dependent resistivity
d) Resistivity with a moderate value
Answer: Correct option will be: (a) Nearly no resistance.
Reason: Semiconductors are materials that can conduct current with nearly no resistance at very low temperatures (example: Lead at–270oC ). As a result, there is a tremendous quantity of current flowing through them.
8. Semiconductor resistance____ as temperature rises.
a) reduces
b) increases
c) remains constant
d) initially increases and then drops
Answer: Correct option will be: (a) reduces.
9. The conductor’s resistance is proportional to:
a) its length
b) its cross-sectional area
c) its temperature
d) its resistivity
Answer: Correct option will be: (a) its length.
10. The most efficient semiconductor material is____.
a) Silicon
b) Germanium
c) Carbon
d) All the mentioned
Answer: Correct option will be (d) all the mentioned.
11. The semiconductor’s conductivity is determined by:
a) electrons in pairs
b) holes in pairs
c) None of these are correct.
d) Both a and b are correct.
Answer: Correct option will be: (d) Both a and b are correct.
12. Ions are electrically charged particles. They are created when an atom:
a) Adds electrons
b) gains or loses electrons
c) shares electrons
d) loses electrons
Answer: Correct option will be: (b) Gains or loses electrons.
Reason: when an atom gains an electron, it becomes a negatively charged particle dur to excess of electrons and when it loses electrons it becomes positively charged particle due to lack of electrons.
13. What are the advantages of using metals to make electrical wire?
a) Metals are rigid and do not bend.
b) Metals can store a lot of heat.
c) Metals are good insulators
d) Metals are electrical conductors.
Answer: Correct option will be: (d) Metals are electrical conductors.
14. What does a conductor and an insulator do not have in common?
a) A conductor does not allow electricity to flow freely through it, whereas an insulator does.
b) An insulator does not allow electricity to flow freely through it, whereas a conductor does.
c) A conductor is not magnetic, while an insulator is.
d) An insulator is not magnetic, whereas a conductor is.
Answer: Correct option will be: (b) An insulator does not allow electricity to flow freely through it, whereas a conductor does.
15. Mittens are useful for keeping your hands warm in the winter because they:
a) They are heat conductors.
b) They’re a little fuzzy.
c) They are electrical energy conductors.
d) They function as insulators.
Answer: Correct option will be: (d) They function as insulators.
16. Rings made of ceramic are used as:
a) Fusion agent
b) Coupler with high strength
c) Insulator
d) impedance regulator
Answer: Correct option will be: (c) Insulator.
Reason: Ceramics are made up of amorphous or glassy solids that are hard and brittle. These materials have a combination of ionic and covalent bonds. Because electrons cannot travel freely, they act as thermal and electrical insulators.
17. Which of the mentioned materials has a negative temperature coefficient of resistance?
a) Copper
b) Nichrome
c) Aluminum
d) Mica
Answer: Correct option will be: (d) Mica.
Reason: The temperature coefficient of non-conductor and semiconductor materials is negative, whereas the temperature coefficient of metal conductors is positive.
18. Which of the following materials are poor conductors of electricity?
a) Copper
b) Aluminum
c) silver
d) Distilled water
Answer: Correct option will be: (d)Distilled water.
Reason: Because it is not ionized, pure water is a poor conductor of electricity. The movement of ions in liquids under the influence of an electric field aids in the conduction of electricity, and pure water is not ionized.
19. Which of the materials below has the best electrical conductivity?
a) Steel
b) Copper
c) Silver
d) Lead
Answer: Correct option will be: (c) Silver.
