Friday, April 8, 2016

Objective Questions on Electronics Engineering:Semiconductors

Objective Questions on Electronics Engineering:Semiconductors
Free questions for GATE SAIL ONGC and other exams
MCQ on Semiconductors

1. An electrically neutral  semiconductor
(i) has no majority carriers
(ii) has no minority carriers
(iii) has no free charge carriers
(iv) has equal amounts of positive and negative charges.

2.The process by which impurities are added to a pure semiconductor is
(i) Diffusing
(ii) Drift
(iii) Doping
(iv) Mixing

3. When holes leave the p-material to fill electrons in the n—material the process is called
(i) Mixing
(ii) Depletion
(iii) Diffusion
 (iv) Depletion

4. JCBO current is
(i) Small in silicon than in germanium transistors
(ii) increases with temperature
(iii) depends on base doping
(iv) depends on eb jn bias

5. Atomic bonding most common in semi conductor is
(i) Metallic
(ii) Ionic
(iii) Covalent
(iv) Chemical

6. When thermally generated holes & electrons gain enough energy from the reversed biased source of a

Zener diode to produce new current carriers it is called
(i) Avalanche Breakdown
(ii) Reverse Breakdown
(iii) Zener Breakdown
(iv) Low voltage eakdown

7. Depletion region in a pn diode is due to
(i) reverse biasing
(ii) forward biasing
(iii) An area created by  crystal doping
(iv) An area void of  current carriers
8. Conventional biasing of a bipolar transistor has
(i) EB forward biased & CB forward biased
(ii) EB reversed biased & CB forward biased
(iii)EB forward biased & CB reverse biased
(iv)EB reverse biased & CB reverse biased,
9. The emitter region in the NPN transistor is more heavily doped than base region so that
(i) flow across the base region will be mainly of holes
(ii) flow across the base regions will be mainly of electrons
(iii) base current is low
(iv) base current is high.

10. Barrier potential for silicon diode
(i) .3V
(ii) .4 V
(iii) .1 V
(iv) .7 V

11. When an atom either gains or loses an electron it is said to be
(i) ionized
(ii bonded
(iii) Excited
(v) an acceptor

12. A strong electric field across a p-N junction that causes covalent bonds to break apart
(i) It is called avalanche breakdown
(ii) It is called reverse breakdown
(iii) It is called Lever breakdown
(iv) It is called Low voltage breakdown

13. Depletion regioin in a pn junction diode
consists of
(i) Mobile donor ions
(ii) Mobile acceptor ions
(iii) Mobile donor & acceptor ions
(iv) majority cairiers
14. The largest current flow of a bipolar transistor occurs
(i) In the emitter
(ii) In the base
(iii) In the collector
(iv) through the collector base

15. Any semiconductor material has a valence of electrons V
(1) 4
(ii)6
(iii)8
(iv)3 or 5













Answers
1 iv
2.iii
3.iii
4. iii
5 iii
6. i
7 ii
8 iii
9 ii
10 iv
11 i
12.i
13.iii
14. i
15 i

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