Physics - Solids and Semiconductor devices

Question - 1

The unit cell of silicon is a

  • A simple cube
  • B body-centred cube
  • C face centred cube
  • D hexagonal

Question - 2

The electron distribution of an atom of silicon is

  • A 2,10,2
  • B 2,8,4
  • C 2,7,5
  • D 2,4,8

Question - 3

Copper has no hole current because

  • A it has large forbidden gap
  • B it has no valency band
  • C it has full electron gas
  • D it has overlapping valency and conduction bands

Question - 4

Conduction electrons have more mobility than holes because they

  • A are lighter
  • B experience collisions less frequently
  • C need less energy to move them
  • D have negative charge

Question - 5

In a semiconducting material,

  • A both holes and electrons move in valency band
  • B both holes and electrons move in conduction band
  • C holes move in valency band whereas free electrons move in conduction band
  • D holes move in conduction band whereas free electrons move in valency band

Question - 6

Consider the STATEMENTS:

A. Single isolated atoms have energy levels and no energy bands

B. solids have energy bands

C. There is forbidden energy gap between any two permitted energy levels within an atom

  • A if A is correct only
  • B if A, and B are correct only
  • C if A,B and C are correct
  • D If B is correct only

Question - 7

Sodium chloride crystal is by nature

  • A dielectric
  • B conductor
  • C semiconductor
  • D metal

Question - 8

Sodium chloride solution in water is by nature

  • A conductor
  • B insulator
  • C semi conductor
  • D metal

Question - 9

Sodium chloride is

  • A ionic crystal
  • B covalent crystal
  • C semi-conductor
  • D insulator

Question - 10

Solid paraffin and sulphur have

  • A metalic binding forces
  • B ionic binding forces
  • C covalent binding forces
  • D van der Wala's binding forces
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