# FACTS Questions and Answers – Diode PN Junction & Transistor – Set 2

This set of FACTS Question Bank focuses on “Diode PN Junction & Transistor – Set 2”.

1. In a diode, ________ are the majority carriers of the p-layer.
a) holes
b) electrons
c) protons
d) neutrons

Explanation: In a diode, holes are the majority carriers of the p-layer. Holes carry positive charges. In absence of any external field, some holes diffuse from p-side to n-side across the p-n junction.

2. In a diode, ________ are the majority carriers of the n-layer.
a) holes
b) electrons
c) protons
d) neutrons

Explanation: In a diode, electrons are the majority carriers of the n-layer. Electrons carry negative charges. In absence of any external field, some electrons diffuse from n-side to p-side across the p-n junction.

3. In a diode, ________ are the minority carriers of the p-layer.
a) holes
b) electrons
c) protons
d) neutrons

Explanation: In a diode, electrons are the minority carriers of the p-layer. This is because in the p-layer, holes outnumber the quantity of free electrons but it contains both these particles. These minority carriers or electrons in the p-layer do carry negative charges.

4. In a diode, ________ are the minority carriers of the n-layer.
a) holes
b) electrons
c) protons
d) neutrons

Explanation: In a diode, holes are the minority carriers of the p-layer. This is because in the n-layer, free electrons outnumber the quantity of holes but it contains both these particles. These minority carriers or holes in the n-layer do carry positive charges.

5. In a transistor, the arrow indicates the ________
a) direction of current
b) direction of voltage
c) direction of alignment
d) direction of breakdown

Explanation: In a transistor, the arrow indicates the direction of current. The emitter always carries the arrow symbol. The arrow is either pointing towards the base or away from the base. Accordingly the transistor configuration can be easily pointed out.

6. A transistor can be of ________
a) PNP type only
b) PNPN type only
c) NPN type only
d) NPN or PNP type

Explanation: A transistor can be of PNP type or NPN type. The PNP type and NPN type transistors are structurally different and can be categorically symbolized indicating the difference of configuration with the help of an arrow in the respective symbol.

7. In PN diode and PNP type or NPN type transistor N stands for ________
a) negative charge
b) neutral charge
c) native charge
d) nodal charge

Explanation: In PN diode and PNP type or NPN type transistor N stands for ‘N’ stands for ‘negative charge’ which indicates the net negative charge of the electrode due to excess of electrons in it. Again ‘P’ stands for ‘positive charge’ which indicates the net positive charge of the electrode due to deficit of electrons in it.

8. A transistor application exhibits ________
a) only common base configuration
b) only common emitter configuration
c) only common collector configuration
d) common emitter or common collector or common base configurations

Explanation: A transistor application exhibits any of the following three configurations. They are common emitter [CE], common collector [CC] and common base [CB] configurations. These configurations find use in various applications with respect to their different characteristics displayed.

9. What is EHP?
a) Electron Hole Pairs
b) Electron Hole Permeance
c) Electron Hole Passiveness
d) Electron Hole Parity

Explanation: The abbreviation ‘EHP’ stand for ‘Electron Hole Pairs’. On breaking the covalent bonds of the crystalline structure, the electrons escape from the bonds and become free ones to move freely. As a result ‘holes’ are created due to deficient of electrons and we get EHP.

10. In ________, at any temperature above 0°K, some of the electrons obtain enough energy to break their covalent bonds and jump to the conduction band.
a) insulators
b) capacitances
c) resistors
d) semiconductors

Explanation: In semiconductors, at 0°K, all the electrons are shared among the adjacent atoms to form the covalent bonds. However, at any temperature above 0°K, some of the electrons obtain enough energy to break their covalent bonds and jump to the conduction band. This happens because the gap between the valence and conduction bands is small which the free electrons pass at temperature above 0°K.

11. In ________, the valence band and the conduction bands overlap.
a) insulators
b) conductors
c) resistors
d) semiconductors

Explanation: In conductors, the valence band and the conduction bands overlap each other. So, there remains no or negligible forbidden band in the lattice network of conductors. Thus, the conductors possess large number of free electrons across the material for the purpose of conduction when required.

12. The band/bands of energy exhibited by a crystalline lattice network is/are ________
a) valence band, forbidden band and conduction band
b) valence band
c) forbidden band
d) valence band

Explanation: The bands of energy exhibited by a crystalline lattice network are valence band, forbidden band and conduction band. The difference between the valence band and conduction band is given by the forbidden band. This forbidden band dictates the behavior of a material.

13. Semiconductors can be ________
a) only intrinsic
b) only extrinsic
c) intrinsic or extrinsic
d) neither intrinsic nor extrinsic

Explanation: Semiconductors can be intrinsic or extrinsic. It depends on whether the semiconductors are doped. Intrinsic ones are those which are exhibiting this property due to its inherent nature. And semiconductors when doped with desired impurities, become extrinsic.

14. In ________ semiconductors, free electrons and holes are in equilibrium.
a) intrinsic
b) extrinsic
c) intrinsic or extrinsic
d) neither intrinsic nor extrinsic

Explanation: In intrinsic semiconductors, free electrons and holes are in equilibrium. This is because these are produced by the inherent property of the semiconductors by the principle of EHP generation. However, n extrinsic semiconductors, free electrons and holes are NOT in equilibrium.

15. Only n-type doping is practiced in semiconductors.
a) True
b) False

Explanation: Doping practiced in semiconductors, can be n-type or p-type. The example of n-type doping is adding phosphorous to silicon crystal lattice. The example of n-type doping is adding boron to silicon crystal lattice.

Sanfoundry Global Education & Learning Series – Flexible AC Transmission System (FACTS).

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