Physics - Semiconductor Electronics - Quiz-3

On increasing the reverse bias to a large value in a PN-junction diode, current

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Increases slowly
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Remains fixed
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Suddenly increases
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Decreases slowly

In the case of forward biasing of PN-junction, which one of the following figures correctly depicts the direction of flow of carriers

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1
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2
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3
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4

A semiconductor device is connected in a series circuit with a battery and a resistance. A current is found to pass through the circuit. If the polarity of the battery is reversed, the current drops almost to zero. The device may be

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A P-type semiconductor
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An N-type semiconductor
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A PN-junction
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An intrinsic semiconductor

The approximate ratio of resistances in the forward and reverse bias of the P-N junction diode is:
(a) $10^{2} : 1$ (b) $10^{- 2} : 1$
(c) $1 : 10^{- 4}$ (d) $1 : 10^{4}$

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1
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2
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3
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4

In a junction diode, the holes are due to

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Protons
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Neutrons
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Extra electrons
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Missing of electrons

In forward bias, the width of potential barrier in a P-N junction diode

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Increases
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Decreases
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Remains constant
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First increases then decreases

The cause of the potential barrier in a P-N diode is

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Depletion of positive charges near the junction
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Concentration of positive charges near the junction
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Depletion of negative charges near the junction
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Concentration of positive and negative charges near the junction

In a PN-junction diode not connected to any circuit

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The potential is the same everywhere
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The P-type is at higher potential than the N-type side
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There is an electric field at the junction directed from the N- type side to the P- type side
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There is an electric field at the junction directed from the P-type side to the N-type side

Which of the following statements is not true

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The resistance of intrinsic semiconductors decrease with increase of temperature
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Doping pure with trivalent impurities give P-type semiconductors
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The majority carriers in N-type semiconductors are holes
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A PN-junction can act as a semiconductor diode

The dominant mechanisms for motion of charge carriers in forward and reverse biased silicon P-N junctions are

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Drift in forward bias, diffusion in reverse bias
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Diffusion in forward bias, drift in reverse bias
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Diffusion in both forward and reverse bias
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Drift in both forward and reverse bias

Which one is reverse-biased

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1
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2
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3
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4

Which one is in forward bias

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1
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2
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3
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4

The reason of current flow in P-N junction in forward bias is

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Drifting of charge carriers
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Minority charge carriers
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Diffusion of charge carriers
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All of these

The resistance of a reverse biased P-N junction diode is about

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1 ohm
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$10^{2}$ ohm
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$10^{3}$ ohm
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$10^{6}$ ohm

Avalanche breakdown is due to

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Collision of minority charge carrier
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Increase in depletion layer thickness
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Decrease in depletion layer thickness
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None of these

Zener breakdown in a semi-conductor diode occurs when

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Forward current exceeds certain value
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Reverse bias exceeds certain value
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Forward bias exceeds certain value
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Potential barrier is reduced to zero

When forward bias is applied to a P-N junction, then what happens to the potential barrier $V_{B}$ , and the width of charge depleted region x

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$V_{B}$ increases, x decreases
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$V_{B}$ decreases, x increases
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$V_{B}$ increases, x increases
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$V_{B}$ decreases, x decreases

Function of rectifier is

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To convert ac into dc
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To convert dc into ac
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Both (a) and (b)
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None of these

When the P end of P-N junction is connected to the negative terminal of the battery and the N end to the positive terminal of the battery, then the P-N junction behaves like

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A conductor
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An insulator
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A super-conductor
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A semi-conductor

A potential barrier of 0.50 V exists across a P-N junction. If the depletion region is $5.0 \times 10^{- 7}$ m wide, the intensity of the electric field in this region is

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(1) $1.0 \times 10^{6} V / m$
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(2) $1.0 \times 10^{5} V / m$
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(3) $2.0 \times 10^{5} V / m$
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(4) $2.0 \times 10^{6} V / m$

If no external voltage is applied across P-N junction, there would be

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No electric field across the junction
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An electric field pointing from N-type to P-type side across the junction
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An electric field pointing from P-type to N-type side across the junction
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A temporary electric field during formation of P-N junction that would subsequently disappear

Barrier potential of a P-N junction diode does not depend on

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Temperature
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Forward bias
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Doping density
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Diode design (shape and size)

The diode shown in the circuit is a silicon diode. The potential difference between the points A and B will be

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6 V
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0.6 V
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0.7 V
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0 V

Zener breakdown takes place if

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Doped impurity is low
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Doped impurity is high
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Less impurity in N-part
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Less impurity in P-type

The correct symbol for zener diode is:

Which one of the following statements is not correct

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A diode does not obey Ohm's law
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A PN junction diode symbol shows an arrow identifying the direction of current (forward) flow
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An ideal diode is an open switch
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An ideal diode is an ideal one way conductor

A semiconductor X is made by doping a germanium crystal with arsenic (Z = 33). A second semiconductor Y is made by doping germanium with indium (Z = 49). The two are joined end to end and connected to a battery as shown. Which of the following statements is correct