Semiconductor mcqs 200 +

semiconductor mcqs 200 +
special purpose diodes mcq

Q1.The semiconductor materials have ________

Free electrons

Holes

Both a and b

None of the above

2.By adding pentavalent impurity atoms to an intrinsic semiconductor material, the number of ________ increased

Electrons

Both a and b

None of the above

3.__________ is an example of semiconductor

Capacitors

Op-amps

all

4.The resistivity of the silicon is __________

0.46Ωm

100Ωm

210Ωm

640Ωm

5.How many outer shell valence electrons does silicon have?
One

Two

Three

Four

6.The electrical conductivity of semiconductor lies in ___________

Inductor

Conductor

Both a and b

None of the above

7.The drift current density effected by _______

An electric filed

Concentration gradient in holes

Concentration gradient in free electrons

All of the above

8. For an intrinsic semiconductor material to have more holes, they are doped with ________atoms
Trivalent impurity

Pentavalent impurity

Both a and b

None of the above

9. How many valence electrons do trivalent impurity atoms have in their valence shell?
One

Two

Three

Four

10. The majority charge carriers in N-type semiconductor is __________
Holes

Electrons

Both a and b

None of the above

11. Which one is an insulator example?
Glass

Copper

Phosphorous

None of the above

12. Which one is a donor example?


Boron

Copper

Phosphorous

None of the above

13. The diffusion current density effected by _____
Concentration gradient in the hole

Concentration gradient in free electrons

Both a and b

None of the above

14. The semiconductors doped with trivalent atoms are ________ type of semiconductor

N-type

P-type

Both a and b

None of the above

15. The doping process converts intrinsic semiconductor material into extrinsic semiconductor material
True

False

16. In P-type semiconductor ________ are the majority charge carriers
Electrons

Holes

Both a and b

None of the above

17.A semiconductor is formed by ……… bonds.

Covalent

Electrovalent

Co-ordinate

None of the above

 18.A semiconductor has ………… temperature coefficient of resistance.

Positive

Zero

Negative

None of the above

19.The most commonly used semiconductor is ………..

Germanium

Silicon

Carbon

Sulphur

20.A semiconductor has generally ……………… valence electrons.

2

3

6

4

21.The resistivity of a pure silicon is about ……………

100 Ω cm

6000 Ω cm

3 x 105 Ω m

6 x 10-8 Ω cm

22.The resistivity of pure germanium under standard conditions is about ……….

6 x 104Ω cm

60Ω cm

3 x 106Ω cm

6 x 10-4Ω cm

23.When a pure semiconductor is heated, its resistance …………..

Goes up

Goes down

Remains the same

Can’t say

24.The strength of a semiconductor crystal comes from ……..

Forces between nuclei

Forces between protons

Electron-pair bonds

None of the above

25.Addition of pentavalent impurity to a semiconductor creates many ……..

Free electrons

Holes

Valence electrons

Bound electrons

26.An n-type semiconductor is ………

Positively charged

Negatively charged

Electrically neutral

None of the above

27.A hole in a semiconductor is defined as …………….

A free electron

The incomplete part of an electron pair bond

A free proton

A free neutron

28.A hole and electron in close proximity would tend to ……….

Repel each other

Attract each other

Have no effect on each other

None of the above

29.In a semiconductor, current conduction is due to ……..

Only holes

Only free electrons

Holes and free electrons

None of the above

30.The random motion of holes and free electrons due to thermal agitation is called ……….

Diffusion

Pressure

Ionisation

None of the above

31.A forward biased p-n junction diode has a resistance of the order of

Ω ohms

None of the above

32.In the depletion region of a p-n junction, there is a shortage of ……..

Acceptor ions

Holes and electrons

Donor ions

None of the above

33.A reverse bias p-n junction has …………

Very narrow depletion layer

Almost no current

Very low resistance

Large current flow

34.A p-n junction acts as a ……….

Controlled switch

Bidirectional switch

Unidirectional switch

None of the above

35.A reverse biased p-n junction has resistance of the order of

Ω

None of the above

36.The leakage current across a p-n junction is due to …………..

Minority carriers

Majority carriers

Junction capacitance

None of the above

37.With forward bias to a p-n junction , the width of depletion layer ………

Decreases

Increases

Remains the same

None of the above

38.In an intrinsic semiconductor, the number of free electrons ………

Equals the number of holes

Is greater than the number of holes

Is less than the number of holes

None of the above

39.At absolute temperature, an intrinsic semiconductor has ……….

A few free electrons

Many holes

Many free electrons

No holes or free electrons

40. Under normal conditions a diode conducts current when it is ……………

reverse biased

forward biased

avalanched

saturated

41.The term bias in electronics usually means ……….

the value of ac voltage in the signal.

the condition of current through a pn junction.

the value of dc voltages for the device to operate properly.

the status of the diode.

42.The battery connections required to forward bias a p-n junction are ……

+ve terminal to p and –ve terminal to n

-ve terminal to p and +ve terminal to n

-ve terminal to p and –ve terminal to n

None of the above

43.A reverse bias p-n junction has …………

wide depletion layer

Large current

Very low resistance

Large current flow

44.The resistivity of a semiconductor ____________ conductors and insulators

More than that of

Lies between

Less than that of

None of the above

45.The resistivity of pure silicon is about___________

100 Ω cm

60,000 Ω cm

3 × 106 Ω cm

1.6 × 10−8 Ω cm

46.The relation between the number of free electrons in semiconductor and its temperature is given as

n∝T

n∝T2

n∝T3/2

n∝√T

47.Which of the following does the resistivity of a semiconductor depend upon?

Length of the semiconductor

Atomic nature of the semiconductor

Shape and atomic nature of the semiconductor

Shape of semiconductor

48.Which of the following statements is true about extrinsic semiconductors?

The gap between the conduction band and the valence bond is more than 16 eV

The gap between the conduction band and the valence bond is about 1 eV

The gap between the conduction band and valence band is 100 eV and more

The conduction band and the valence band overlap.

 49.How many valence electrons do trivalent impurities have?

2

3

4

5

50.How many valence electrons does a pentavalent impurity have?

3

4

5

6

51.Which among the following is the most commonly used semiconductor?

Silicon

Carbon

Germanium

Sulphur