Electrical Engineering Materials MCQs

1.Which factor primarily influences the concentration of minority carriers?

2.How does the electron current in the conduction band compare to the hole current in the valence band?

It is equal to the hole currentIt is smaller than the hole currentIt is larger than the hole currentIt could be any of the above

3.What is the band gap energy of germanium?

0.15 electron volts0.25 electron volts0.5 electron volts0.7 electron volts

4.Which type of element, containing three valence electrons, is commonly used as a dopant in semiconductors?

5.Which material contains the lowest proportion of carbon?

6.How does the electrical conductivity of an extrinsic semiconductor change as the temperature rises?

It reducesIt goes upIt stays unchanged

7.Which of the following statements about holes is incorrect?

Holes are present only in specific types of semiconductors.Holes can appear in all materials, including conductors.Holes are capable of carrying electric current.Holes can be treated as positive charge carriers.

8.If the Hall coefficient of a substance is measured to be zero, what type of material is it most likely?

9.What is the relative permeability of a superconducting metal when it is in its superconducting phase?

10.Which of these elements influence the resistivity of metallic materials?

11.What causes the surface resistance of an insulating material to decrease?

Presence of smoke and dirt in the environmentMoisture content in the airBoth smoke and dirt along with atmospheric humidityNeither smoke and dirt nor humidity

12.In conductors, the flow of electric current is primarily caused by the movement of which particles?

13.How does the presence of moisture impact the properties of insulating materials?

Reduces the dielectric constantLowers the dielectric strengthDecreases the insulation resistanceRaises the dielectric lossAll of the above effects occur

14.What is the characteristic size of the forbidden energy gap in an insulating material?

15.What do we call a conductor whose resistance does not follow Ohm's law?

non-linear conductorreverse conductorpoor conductorinsulator

16.Why is aluminium increasingly being used as a substitute for copper in India?

Because aluminium is more flexible and easier to shape than copperSince aluminium is abundant, cost-effective, and lighter compared to copperDue to aluminium having a lower electrical resistivity than copperBecause aluminium exhibits a smaller temperature coefficient than copper