Copper is harder than mica
Mica and copper are equally hard
Mica is harder than copper
None of the above
Answer is Wrong!
Answer is Right!
The correct answer is: C. Mica is harder than copper.
Mica is a naturally occurring mineral that is composed of sheet silicates. It is a very good electrical insulator and is often used in commutators. Copper is a metal that is also used in commutators. It is a good conductor of electricity and is also relatively hard. However, mica is harder than copper. This means that mica is less likely to wear away than copper. This is important in commutators, as the commutator is a part of an electric motor that is constantly in contact with other parts. If the commutator were to wear away, it would not be able to function properly.
Here is a brief explanation of each option:
- A. Copper is harder than mica. This is not true. Mica is harder than copper.
- B. Mica and copper are equally hard. This is also not true. Mica is harder than copper.
- D. None of the above. This is the correct answer.