Semiconductor Electronics : Materials, Devices and Simple Circuits Easy Questions and Answers | Page - 6

Semiconductor Electronics : Materials, Devices and Simple Circuits

Zener diode is used for

1. amplification
1. rectification
1. stabilisation
1. producing oscillations in an oscillator

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At a certain reverse bias voltage, zener diode allows current to flow through it and hence maintains the voltage supplied to any load Hence, it is used for stabilisation.

Correct Option: C

At a certain reverse bias voltage, zener diode allows current to flow through it and hence maintains the voltage supplied to any load Hence, it is used for stabilisation.

In an unbiased p-n junction, holes diffuse from the p-region to n-region because of

1. the potential difference across the p-n junction
1. the attraction of free electrons of n-region
1. the higher hole concentration in p-region than that in n-region
1. the higher concentration of electrons in the n-region than that in the p-region

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In p-region of p-n junction holes concentration > electrons concentration and in n-region electrons concentration > holes concentration.

Correct Option: C

In p-region of p-n junction holes concentration > electrons concentration and in n-region electrons concentration > holes concentration.

Two ideal diodes are connected to a battery as shown in the circuit. The current supplied by the battery is :

1. 0.75 A
1. zero
1. 0.25 A
1. 0.5 A

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Here D₁ is in forward bias and D₂ is in reverse bias so, D₁ will conduct and D₂ will not conduct. Thus, no current will flow through DC.
I = ΔV = 5 = 1 Amp.
R 10 2

Correct Option: D

Here D₁ is in forward bias and D₂ is in reverse bias so, D₁ will conduct and D₂ will not conduct. Thus, no current will flow through DC.
I = ΔV = 5 = 1 Amp.
R 10 2

C and Si both have same lattice structure, having 4 bonding electrons in each. However, C is insulator whereas Si is intrinsic semiconductor. This is because :

1. In case of C the valence band is not completely filled at absolute zero temperature.
1. In case of C the conduction band is partly filled even at absolute zero temperature.
1. The four bonding electrons in the case of C lie in the second orbit, whereas in the case of Si they lie in the third.
1. The four bonding electrons in the case of C lie in the third orbit, whereas for Si they lie in the fourth orbit.

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Electronic configuration of ⁶C
⁶C = 1s², 2s² 2p²
The electronic configuration of ¹⁴Si
¹⁴Si = 1s², 2s² 2p⁶, 3s² 3p²
As they are away from Nucleus, so effect of nucleus is low for Si even for Sn and Pb are almost mettalic.

Correct Option: C

Electronic configuration of ⁶C
⁶C = 1s², 2s² 2p²
The electronic configuration of ¹⁴Si
¹⁴Si = 1s², 2s² 2p⁶, 3s² 3p²
As they are away from Nucleus, so effect of nucleus is low for Si even for Sn and Pb are almost mettalic.

In a n-type semiconductor, which of the following statement is true?

1. Electrons are minority carriers and pentavalent atoms are dopants.
1. Holes are minority carriers and pentavalent atoms are dopants.
1. Holes are majority carriers and trivalent atoms are dopants.
1. Electrons are majority carriers and trivalent atoms are dopants.

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In a n-type semiconductor holes are minority carriers and pentavalent atoms are dopants.

Correct Option: B

In a n-type semiconductor holes are minority carriers and pentavalent atoms are dopants.