Semiconductor Electronics : Materials, Devices and Simple Circuits Easy Questions and Answers | Page - 8

Semiconductor Electronics : Materials, Devices and Simple Circuits

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 forward biasing of the p–n junction

1. the positive terminal of the battery is connected to p–side and the depletion region becomes thick
1. the positive terminal of the battery is connected to n–side and the depletion region becomes thin
1. the positive terminal of the battery is connected to n–side and the depletion region becomes thick
1. the positive terminal of the battery is connected to p–side and the depletion region becomes thin

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In forward biasing of the p-n junction, the positive terminal of the battery is connected to p-side and the negative terminal of the battery is connected to n-side. The depletion region becomes thin.

Correct Option: D

In forward biasing of the p-n junction, the positive terminal of the battery is connected to p-side and the negative terminal of the battery is connected to n-side. The depletion region becomes thin.

If a small amount of antimony is added to germanium crystal

1. it becomes a p–type semiconductor
1. the antimony becomes an acceptor atom
1. there will be more free electrons than holes in the semiconductor
1. its resistance is increased

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When small amount of antimony (pentavalent) is added to germanium crystal then crystal becomes n-type semi conductor. Therefore, there will be more free electrons than holes in the semiconductor.

Correct Option: C

When small amount of antimony (pentavalent) is added to germanium crystal then crystal becomes n-type semi conductor. Therefore, there will be more free electrons than holes in the semiconductor.

In the energy band diagram of a material shown below, the open circles and filled circles denote holes and electrons respectively. The material is

1. an insulator
1. a metal
1. an n-type semiconductor
1. a p-type semiconductor

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For a p-type semiconductor, the acceptor energy level, as shown in the diagram, is slightly above the top E_v of the valence band. With very small supply of energy an electron from the valence band can jump to the level E_A and ionise acceptor negatively.

Correct Option: D

For a p-type semiconductor, the acceptor energy level, as shown in the diagram, is slightly above the top E_v of the valence band. With very small supply of energy an electron from the valence band can jump to the level E_A and ionise acceptor negatively.