Deck 2: Semoconductors

Question 1

The core of an atom consists of all the outer orbits.

Answer 1

False

Question 2

At room temperature,a silicon crystal acts like an insulator.

Answer 2

False

Question 3

The merging of a free electron and a hole is referred to as a

A) merger.
B) combination.
C) restoration.
D) recombination.

Answer 3

D

Question 4

When silicon atoms combine to form a solid,they arrange themselves into an orderly pattern called

A) an orbit.
B) the valence shell.
C) a crystal.
D) a conductor.

Question 5

Doping is a process of adding impurity atoms to an intrinsic crystal to alter its electrical conductivity.

Question 6

Other than germanium,what is another type of semiconductor material generally used?

A) copper
B) helium
C) aluminum
D) silicon

Question 7

Thermal energy produces free electrons and holes in pairs.

Question 8

Intrinsic semiconductor has unequal number of free electrons and holes.

Question 9

A semiconductor is an element with electrical properties between those of a conductor and those of an insulator.

Question 10

How many electrons are in the valence orbit of a silicon crystal?

A) 2
B) 4
C) 8
D) None

Question 11

The valence orbit controls the electrical properties of the atom.

Question 12

How many valence electrons are there in a germanium semiconductor?

A) 1
B) 2
C) 4
D) None

Question 13

The temperature of the surrounding air is called

A) ambient.
B) surround sound.
C) atmospheriC.
D) Centigrade.

Question 14

When the departure of an electron creates a vacancy in the valence orbit,it is called a

A) hole.
B) vacant electron.
C) polarized electron.
D) negative ion.

Question 15

A pure semiconductor is also referred to as

A) a clean room device.
B) intrinsiC.
C) extrinsiC.
D) transistor.

Question 16

A doped semiconductor is called an intrinsic semiconductor.

Question 17

Copper is a good conductor.

Question 18

The valence electron is referred to as a free electron.

Question 19

The amount of time between the creation and disappearance of a free electron is called a

A) light year.
B) millisecond.
C) lifetime.
D) work week.

Question 20

The term used to describe the sharing of valence electrons that gives a crystal solidity is

A) covalent bonding.
B) negative ion.
C) saturation point.
D) reverse bias.

Question 21

Current flows easily in a forward-biased diode.

Question 22

When reverse bias is increased

A) forward current increases.
B) depletion layer widens.
C) depletion layer becomes smaller.
D) the diode becomes polarized.

Question 23

What type of atoms are added to molten silicon in order to increase the number of free electrons?

A) pentavalent
B) trivalent
C) covalent
D) positive

Question 24

What results when the negative battery terminal is connected to the p side of a pn junction,and the positive battery terminal to the n side?

A) forward bias
B) reverse bias
C) avalanche breakdown
D) a short circuit

Question 25

Each pair of positive and negative ions at the pn junction is called a dipole.

Question 26

In an n-type semiconductor,the free electrons are called the

A) minority carriers.
B) majority carriers.
C) holes.
D) ions.

Question 27

A trivalent atom is also called

A) an acceptor atom.
B) a donor atom.
C) copper.
D) a negative ion.

Question 28

As dipoles build up,the region near the pn junction is void of all charges and is called the restoration layer.

Question 29

Reverse bias is achieved when the negative source terminal is connected to the n-type material,and the positive terminal is connected to the p-type material.

Question 30

What is the most popular and useful semiconductor material?

A) silver
B) copper
C) aluminum
D) silicon

Question 31

Each time an electron diffuses across a pn junction,it creates a pair of ions.

Question 32

Silicon that has been doped with a trivalent impurity is called a (an)

A) n-type semiconductor.
B) p-type semiconductor.
C) pn junction.
D) covalent bond.

Question 33

The limit to how much reverse voltage a diode can withstand before it is destroyed is called

A) forward bias.
B) reverse bias.
C) breakup current.
D) breakdown voltage.

Question 34

The border between p-type and n-type crystal is called the

A) pn junction.
B) p-type border.
C) n-type margin.
D) p junction.

Question 35

What type of impurity is added to pure silicon to get an excess of holes?

A) pentavalent
B) trivalent
C) covalent
D) positive

Question 36

When a free electron enters the p region of a junction diode,it becomes a

A) majority carrier.
B) minority carrier.
C) hole.
D) depletion carrier.

Question 37

A silicon diode will allow a continuous current in the forward direction,if the source voltage is

A) greater than 0.7 V.
B) equal to 7.7 V.
C) less than 0.7 V.
D) zero.

Question 38

Silicon that has been doped with a pentavalent impurity is called

A) a p-type semiconductor.
B) an n-type semiconductor.
C) a conductor.
D) an insulator.

Question 39

What is the approximate current level in a reverse-biased diode?

A) 0.7 mA
B) 0.7 A
C) 1.7 A
D) zero

Question 40

What is another name for pn crystal?

A) junction diode
B) bipolar transistor
C) dipole
D) field effect device

Question 41

In a silicon atom,what is the distance between the valence band and the conduction band called?

A) energy gap
B) depletion layer
C) pn junction
D) intrinsic

Question 42

When free electrons fall from the conduction band to the valence band,excess energy

A) is radiated in the form of heat and light.
B) is lost due to valence electrons.
C) is radiated in the form of sound.
D) is gained due to hole flow.

Question 43

What is the term for the temperature inside a diode,right at the pn junction?

A) ambient temperature
B) diode temperature
C) pn temperature
D) junction temperature

Question 44

What is a disadvantage of a germanium device that prevents its prevalent use in modern computers,consumer electronics,and communication circuits?

A) cost
B) weight
C) excessive reverse current
D) excessive forward current

Question 45

What is the term for reverse current on the surface of a crystal?

A) crystal current
B) reverse current
C) surface-leakage current
D) avalanche breakdown current

Question 46

In a semiconductor,thermal energy produces free electrons that go to the next higher-energy band called the

A) radiation band.
B) conduction band.
C) electron band.
D) valence band.

Question 47

In a Light-emitting diode (LED),what lifts the electrons to higher energy levels?

A) constant current source
B) applied voltage
C) valence electrons
D) light

Question 48

The depletion layer does not exist

A) in pn junction diodes.
B) when a diode is first sold.
C) when a diode is first formed.
D) until the holes are injected.

Question 49

When the reverse voltage increases,holes and electrons

A) recombine.
B) move away from the junction.
C) move toward the junction.
D) remain stationary.

Question 50

What type of bias gives free electrons more energy?

A) reverse
B) forward
C) negative
D) positive