Electrical Engineering Materials MCQ Questions & Answers | Electrical Engineering

Selenium is an intrinsic semiconductor.

An intrinsic semiconductor is one that is pure and contains no significant dopants or impurities. In the case of selenium, it is an intrinsic semiconductor when it is in its pure form. Intrinsic semiconductors have equal numbers of electrons and holes, allowing for the flow of current under certain conditions.

Extrinsic semiconductors, on the other hand, are those that have been intentionally doped with impurities to alter their electrical properties. These can be further categorized into N-type and P-type semiconductors based on the type of doping introduced.

Therefore, the correct spelling of the term is intrinsic, making Option B the correct

H.R.C. stands for High Rupturing Capacity.
This means the fuse can safely interrupt very high fault currents.
Fuses are designed to protect electrical circuits from overcurrents.
Option A is correct: H.R.C. fuses typically have a ceramic body for insulation and heat resistance, and metal end caps to connect it to the circuit.
Option B is incorrect: Platinum is expensive and not typically used in fuses.
Option C is incorrect: A heavy cross-section of copper or aluminum would carry a lot of current without blowing, defeating the purpose of a fuse. Fuses need a specifically designed element that melts.
Option D is incorrect: Carbon rods are generally used in resistance applications, not as fuse elements in H.R.C. fuses. Also, carbon has a relatively high resistance, unlike fuse elements that need a very low resistance.