In the tunnel diode, the Fermi level lies

in the energy band gap but closer to the conduction band of n-type semiconductors

inside valence band of p-type and inside conduction band of n-type semiconductors

in the energy band gap but closer to the conduction band of n-type semiconductors

in the energy band gap but closer to the valence band of = p-type semiconductors

in the energy band gap but above valence band of p-type and below conduction band of n-type semiconductors

A basic equivalent circuit of a tunnel diode consists of series inductance Ls, the series resistance Rs, the diode capacitance Cj and the negative resistance = R. the reactive cut-off frequency isi) \(\frac{1}{{2\pi R{C_j}}}\;\sqrt {\frac{R}{{{R_s}}} - 1}\)ii) \(\frac{1}{{2\pi }}\sqrt {\frac{1}{{{L_s}{C_j}}} - \frac{1}{{{{\left( {R{C_j}} \right)}^2}}}} \)iii) \(\frac{1}{{2\pi }}\sqrt {\frac{1}{{{L_s}{C_j}}} + \frac{1}{{{{\left( {R{C_j}} \right)}^2}}}} + \frac{1}{{2\pi }}\;\sqrt {\frac{1}{{R{C_j}}}} \)iv) \(\frac{1}{{2\pi R{C_j}}}\;\sqrt {\frac{R}{{{R_s}}} - 1} + \frac{1}{{2\pi }}\sqrt {\frac{1}{{{L_s}{C_j}}} + \frac{1}{{{{\left( {R{C_j}} \right)}^2}}}} \)Choose the correct answer from the code given below:Code:

(i) is wrong but (ii) is correct

(iv) is correct but (ii) is wrong

(iii) is correct but (iv) is wrong

______ is the maximum reverse voltage that can be applied to the pn junction ______ to the junction.

Barrier voltage, without damage

Peak inverse voltage, without damage

Barrier voltage, without damage

Peak inverse voltage, with damage

During reverse bias operation of a PN junction, a feeble current flow known as ________ which is __________ barrier voltage.

reverse current, independent of

carrier current, independent of

In a forward-biased PN junction diode, the sequence of events that best describes the mechanism of current flow is

injection and subsequent drift and generation of minority carriers

injection, and subsequent diffusion and recombination of minority carriers

injection and subsequent drift and generation of minority carriers

extraction and, and subsequent diffusion and generation of minority carriers

extraction, and subsequent drift and recombination of minority carriers.

Diffusion capacitance of PN Junction Diode ______.

decrease with decreasing current and decreasing temperature

increase with increasing current and increasing temperature

increase with increase current and decreasing temperature

decrease with decreasing current and decreasing temperature

decrease with increasing current and increasing temperature

High resistivity p-n junction diode

A very heavily doped p-n junction diode

Match the two lists and choose the correct answer from the code given below:List IList II(a) Foster Seeley discriminator(i) Optical fiber(b) Envelope detector(ii) Microwave(c) APD detector(iii) AM wave(d) PIN detector(iv) FM signal

(a) – (ii), (b) – (iv), (c) – (i), (d) – (iii)

(a) – (iii), (b) – (iv), (c) – (ii), (d) – (i)

(a) – (ii), (b) – (iii), (c) – (i), (d) – (iv)

(a) – (iv), (b) – (iii), (c) – (i), (d) – (ii)

(a) – (ii), (b) – (iv), (c) – (i), (d) – (iii)

In forward blocking region of SCR which of the following statements is correct?

Junctions J1 and J2 are in forward biased while junction J3 is in reversed biased

Outer junction J1 and J3 are in reversed biased while middle junction J2 is forward biased

Outer junctions J1 and J3 are in forward biased while J2 is in reversed biased

Junctions J1 and J2 are in forward biased while junction J3 is in reversed biased

All the three junctions J1, J2 and J3 are in forward biased

Choose the INCORRECT statement with regard to a forward biased pn diode.

Current flows in the circuit due to the establishment of low resistance path

The junction offer low resistance to current flow

The potential barrier is constant irrespective of magnitude of the applied voltage

Current flows in the circuit due to the establishment of low resistance path

The potential barrier is reduced and at some forward voltage, it is eliminated

Consider two infinite duration input sequences {x1[n], x2[n]}. When will the Region of Convergence [ROC] of Z-transform of their superposition i.e. {x1[n] + x2[n]} be entire Z plane except possibly at Z = 0 or Z = ∞ ?

When they are left sided sequences

When their linear combination is of finite duration

When they are left sided sequences

When they are right sided sequences

When their linear combination is

A region of negative differential resistance is observed in the current voltage characteristics of a silicon PN junction if

The N-region is heavily doped compared to the P-region

Both the P-region and the N-region are heavily doped

The N-region is heavily doped compared to the P-region

The P-region is heavily doped compared to the N-region

An intrinsic silicon region is inserted between the P-region and the N-region

Nonlinear time varying resistor

Neither current controlled nor voltage controlled resistor

Assertion (A): The reverse saturation current approximately doubles for every 10°C temperature rise for both Si and Ge materials.Reason (R): At room temperature, the p-n junction voltage decreases by about 2.5 mV per °C rise in temperature.

Both A and R are individually true and R is the correct explanation of A

Both A and R are individually true but R is not the correct explanation of A

93 + Mcqs in Pn Junction Diode in Electronic Devices Circuits Page 2 McqOptions

51.	Peak inverse voltage for a full wave rectifier is
A.	Em
B.	2Em
C.	3Em
D.	4Em
Answer» C. 3Em

Discussion

52.	In PN junction diode, the region containing the uncompensated acceptor and donor ions is called _______.
A.	Enhancement region
B.	Cut off region
C.	Diode region
D.	Depletion region
Answer» E.

Discussion

53.	In the tunnel diode, the Fermi level lies
A.	inside valence band of p-type and inside conduction band of n-type semiconductors
B.	in the energy band gap but closer to the conduction band of n-type semiconductors
C.	in the energy band gap but closer to the valence band of = p-type semiconductors
D.	in the energy band gap but above valence band of p-type and below conduction band of n-type semiconductors
Answer» B. in the energy band gap but closer to the conduction band of n-type semiconductors

Discussion

54.	A light emitting diode (L.E.D.) can be made from:
A.	Phosphorescent material
B.	Germanium
C.	Silicon
D.	Gallium arsenid
Answer» E.

Discussion

55.	A potential barrier of 0.50 V exists across a p-n junction. If the depletion region is 5.0 × 10-7 m wide, what is the intensity of the electric field in this region?
A.	1.0 × 106 V/m
B.	2.5 × 10-7 V/m
C.	2.5 × 107 V/m
D.	2.5 × 108 V/m
Answer» B. 2.5 × 10-7 V/m

Discussion

56.	A basic equivalent circuit of a tunnel diode consists of series inductance Ls, the series resistance Rs, the diode capacitance Cj and the negative resistance = R. the reactive cut-off frequency isi) \(\frac{1}{{2\pi R{C_j}}}\;\sqrt {\frac{R}{{{R_s}}} - 1}\)ii) \(\frac{1}{{2\pi }}\sqrt {\frac{1}{{{L_s}{C_j}}} - \frac{1}{{{{\left( {R{C_j}} \right)}^2}}}} \)iii) \(\frac{1}{{2\pi }}\sqrt {\frac{1}{{{L_s}{C_j}}} + \frac{1}{{{{\left( {R{C_j}} \right)}^2}}}} + \frac{1}{{2\pi }}\;\sqrt {\frac{1}{{R{C_j}}}} \)iv) \(\frac{1}{{2\pi R{C_j}}}\;\sqrt {\frac{R}{{{R_s}}} - 1} + \frac{1}{{2\pi }}\sqrt {\frac{1}{{{L_s}{C_j}}} + \frac{1}{{{{\left( {R{C_j}} \right)}^2}}}} \)Choose the correct answer from the code given below:Code:
A.	(i) is wrong but (ii) is correct
B.	(iii) and (iv) are correct
C.	(iv) is correct but (ii) is wrong
D.	(iii) is correct but (iv) is wrong
Answer» B. (iii) and (iv) are correct

Discussion

57.	Breakdown of a P-N diode may occur due to
A.	Thermal instability
B.	Tunneling effect
C.	Avalanche multiplication
D.	All the above
Answer» E.

Discussion

58.	Avalanche breakdown is primarily dependent on the phenomenon of
A.	Doping
B.	Collision
C.	Ionization
D.	Recombination
Answer» C. Ionization

Discussion

59.	______ is the maximum reverse voltage that can be applied to the pn junction ______ to the junction.
A.	Peak inverse voltage, without damage
B.	Barrier voltage, without damage
C.	Maximum power rating, damage
D.	Peak inverse voltage, with damage
Answer» B. Barrier voltage, without damage

Discussion

60.	During reverse bias operation of a PN junction, a feeble current flow known as ________ which is __________ barrier voltage.
A.	reverse current, dependent on
B.	reverse current, independent of
C.	carrier current, dependent on
D.	carrier current, independent of
Answer» C. carrier current, dependent on

Discussion

61.	In a p-n junction solar cell under low injection condition, the one-dimensional continuity equations area) \({G_n} - \frac{{{n_p} - {n_{po}}}}{{{\tau _n}}} + \frac{1}{q}\frac{{d{J_n}}}{{dn}} = 0\)b) \({G_n} + \frac{{{n_p} - {n_{po}}}}{{{\tau _n}}} - \frac{1}{q}\frac{{d{J_n}}}{{dn}} = 0\)c) \({G_p} - \frac{{{P_n} - {P_{no}}}}{{{\tau _p}}} - \frac{1}{q}\frac{{d{J_p}}}{{dn}} = 0\)d) \({G_p} + \frac{{{P_n} - {P_{no}}}}{{{\tau _p}}} - \frac{1}{q}\frac{{d{J_p}}}{{dn}} = 0\)Choose the correct option:
A.	and b) are correct
B.	and d) are correct
C.	and c) are correct
D.	and d) are correct
Answer» D. and d) are correct

Discussion

62.	In a Zener diode shunt voltage regulator, the diode regulates so long as is kept ina) forward conditionb) reverse conditionc) loaded conditiond) unloaded conditionChoose the correct option:
A.	is correct but b) is wrong
B.	is correct but d) is wrong
C.	is correct but d) is wrong
D.	and d are correct
Answer» C. is correct but d) is wrong

Discussion

63.	Between the peak point and the valley point of tunnel diode, there is _____ region
A.	Saturation
B.	Negative resistance
C.	Cut-off
D.	None of the above
Answer» C. Cut-off

Discussion

64.	An ideal diode can be considered as an:
A.	Amplifier
B.	Bi-stable switch
C.	Oscillator
D.	Fuse
Answer» C. Oscillator

Discussion

65.	In a forward-biased PN junction diode, the sequence of events that best describes the mechanism of current flow is
A.	injection, and subsequent diffusion and recombination of minority carriers
B.	injection and subsequent drift and generation of minority carriers
C.	extraction and, and subsequent diffusion and generation of minority carriers
D.	extraction, and subsequent drift and recombination of minority carriers.
Answer» B. injection and subsequent drift and generation of minority carriers

Discussion

66.	Diffusion capacitance of PN Junction Diode ______.
A.	increase with increasing current and increasing temperature
B.	increase with increase current and decreasing temperature
C.	decrease with decreasing current and decreasing temperature
D.	decrease with increasing current and increasing temperature
Answer» C. decrease with decreasing current and decreasing temperature

Discussion

67.	A Zener diode:(a) has a sharp breakdown at a low forward voltage(b) has a sharp breakdown at a low reverse voltage(c) can be used for voltage regulation(d) has a negative resistance regionCode:
A.	(a), (c) and (d) are correct
B.	(b), (c) and (a) are correct
C.	(a) and (b) are correct
D.	(b) and (c) are correct
Answer» E.

Discussion

68.	In mercury arc rectifier, mercury is used as
A.	Cathode
B.	Conducting medium
C.	Ionizing medium
D.	Electron accelerator
Answer» B. Conducting medium

Discussion

69.	Ionization within a P-N junction causes a layer on each side of the barrier called the
A.	Junction
B.	Depletion region
C.	Barrier voltage
D.	Forward voltage
Answer» C. Barrier voltage

Discussion

70.	A tunnel diode is
A.	High resistivity p-n junction diode
B.	A slow switching device
C.	A very heavily doped p-n junction diode
D.	None of the above
Answer» D. None of the above

Discussion

71.	Match the two lists and choose the correct answer from the code given below:List IList II(a) Foster Seeley discriminator(i) Optical fiber(b) Envelope detector(ii) Microwave(c) APD detector(iii) AM wave(d) PIN detector(iv) FM signal
A.	(a) – (iii), (b) – (iv), (c) – (ii), (d) – (i)
B.	(a) – (ii), (b) – (iii), (c) – (i), (d) – (iv)
C.	(a) – (iv), (b) – (iii), (c) – (i), (d) – (ii)
D.	(a) – (ii), (b) – (iv), (c) – (i), (d) – (iii)
Answer» D. (a) – (ii), (b) – (iv), (c) – (i), (d) – (iii)

Discussion

72.	A forward biased PN junction will acts as a/an:
A.	Closed switch
B.	Amplifier
C.	Attenuator
D.	Open switch
Answer» B. Amplifier

Discussion

73.	In forward blocking region of SCR which of the following statements is correct?
A.	Outer junction J1 and J3 are in reversed biased while middle junction J2 is forward biased
B.	Outer junctions J1 and J3 are in forward biased while J2 is in reversed biased
C.	Junctions J1 and J2 are in forward biased while junction J3 is in reversed biased
D.	All the three junctions J1, J2 and J3 are in forward biased
Answer» C. Junctions J1 and J2 are in forward biased while junction J3 is in reversed biased

Discussion

74.	Choose the INCORRECT statement with regard to a forward biased pn diode.
A.	The junction offer low resistance to current flow
B.	The potential barrier is constant irrespective of magnitude of the applied voltage
C.	Current flows in the circuit due to the establishment of low resistance path
D.	The potential barrier is reduced and at some forward voltage, it is eliminated
Answer» C. Current flows in the circuit due to the establishment of low resistance path

Discussion

75.	For a PN junction diode, width of space charge region increases as?
A.	Forward bias voltage increases
B.	Reverse bias voltage increases
C.	Forward bias voltage reduces
D.	Reverse bias voltage reduces
Answer» C. Forward bias voltage reduces

Discussion

76.	Find the reverse saturation current at 35° C for a junction which has I0 = 30 nA at 25° C.
A.	25 nA
B.	40 nA
C.	60 nA
D.	20 nA
Answer» D. 20 nA

Discussion

77.	Consider two infinite duration input sequences {x1[n], x2[n]}. When will the Region of Convergence [ROC] of Z-transform of their superposition i.e. {x1[n] + x2[n]} be entire Z plane except possibly at Z = 0 or Z = ∞ ?
A.	When their linear combination is of finite duration
B.	When they are left sided sequences
C.	When they are right sided sequences
D.	When their linear combination is
Answer» B. When they are left sided sequences

Discussion

78.	A region of negative differential resistance is observed in the current voltage characteristics of a silicon PN junction if
A.	Both the P-region and the N-region are heavily doped
B.	The N-region is heavily doped compared to the P-region
C.	The P-region is heavily doped compared to the N-region
D.	An intrinsic silicon region is inserted between the P-region and the N-region
Answer» B. The N-region is heavily doped compared to the P-region

Discussion

79.	An ideal diode is:
A.	Current controlled resistor
B.	Voltage controlled resistor
C.	Nonlinear time varying resistor
D.	Neither current controlled nor voltage controlled resistor
Answer» E.

Discussion

80.	During the forward biased condition in a diode, the ratio of power dissipated in it to the forward DC current is known as:
A.	peak power rating of the diode
B.	dynamic resistance
C.	forward voltage drop
D.	static resistance
Answer» D. static resistance

Discussion

81.	Depletion layer is found in
A.	p type semiconductors
B.	n type semiconductors
C.	diodes
D.	intrinsic semiconductors
Answer» D. intrinsic semiconductors

Discussion

82.	An n+ - n Silicon device is fabricated with uniform and non-degenerate donor doping concentrations of ND1 = 1 × 1018 cm-3 and ND2 = 1 × 1015 cm-3 corresponding to the n+ and n regions respectively. At the operational temperature T, assume complete impurity ionization, kT/q = 25 mV, and intrinsic carrier concentration to be ni = 1 × 1010 cm-3. What is the magnitude of the built – in potential of this device?
A.	0.748 V
B.	0.460 V
C.	0.288 V
D.	0.173 V
Answer» E.

Discussion

83.	Diffusion capacitance of a PN junction diode ________ with forward bias.
A.	increases
B.	decreases
C.	may increase or decrease
D.	remains the same
Answer» B. decreases

Discussion

84.	A reverse biased PN junction will act as a/an:
A.	Amplifier
B.	Open switch
C.	Attenuator
D.	Closed switch
Answer» C. Attenuator

Discussion

85.	Assertion (A): The reverse saturation current approximately doubles for every 10°C temperature rise for both Si and Ge materials.Reason (R): At room temperature, the p-n junction voltage decreases by about 2.5 mV per °C rise in temperature.
A.	Both A and R are individually true and R is the correct explanation of A
B.	Both A and R are individually true but R is not the correct explanation of A
C.	A is true but R is false
D.	A is false but R is true
Answer» C. A is true but R is false

Discussion

86.	It is possible to measure the voltage across the potential barrier through a voltmeter?
A.	True
B.	False
Answer» C.

Discussion

87.	When the diode is reverse biased with a voltage of 6V and V_bi=0.63V. Calculate the total potential.
A.	6V
B.	6.63V
C.	5.27V
D.	0.63V
Answer» C. 5.27V

Discussion

88.	What is the maximum electric field when V_bi=2V , V_R=5V and width of the semiconductor is 7cm?
A.	-100V/m
B.	-200V/m
C.	100V/m
D.	200V/m
Answer» C. 100V/m

Discussion

89.	During the reverse biased of the diode, the back resistance decrease with the increase of the temperature. Is it true or false?
A.	True
B.	False
Answer» B. False

Discussion

90.	If the voltage of the potential barrier is V₀. A voltage V is applied to the input, at what moment will the barrier disappear?
A.	V< V<sub>0</sub>
B.	V= V<sub>0</sub>
C.	V> V<sub>0</sub>
D.	V<< V<sub>0</sub>
Answer» C. V> V<sub>0</sub>

Discussion

91.	During reverse bias, a small current develops known as
A.	Forward current
B.	Reverse current
C.	Reverse saturation current
D.	Active current
Answer» D. Active current

Discussion

92.	If the positive terminal of the battery is connected to the anode of the diode, then it is known as
A.	Forward biased
B.	Reverse biased
C.	Equilibrium
D.	Schottky barrier
Answer» B. Reverse biased

Discussion

93.	How many junction/s do a diode consist?
A.	0
B.	1
C.	2
D.	3
Answer» C. 2

Discussion

Explore topic-wise MCQs in Electronic Devices Circuits.

Peak inverse voltage for a full wave rectifier is

In PN junction diode, the region containing the uncompensated acceptor and donor ions is called _______.

In the tunnel diode, the Fermi level lies

A light emitting diode (L.E.D.) can be made from:

A potential barrier of 0.50 V exists across a p-n junction. If the depletion region is 5.0 × 10-7 m wide, what is the intensity of the electric field in this region?

Breakdown of a P-N diode may occur due to

Avalanche breakdown is primarily dependent on the phenomenon of

______ is the maximum reverse voltage that can be applied to the pn junction ______ to the junction.

During reverse bias operation of a PN junction, a feeble current flow known as ________ which is __________ barrier voltage.

In a Zener diode shunt voltage regulator, the diode regulates so long as is kept ina) forward conditionb) reverse conditionc) loaded conditiond) unloaded conditionChoose the correct option:

Between the peak point and the valley point of tunnel diode, there is _____ region

An ideal diode can be considered as an:

In a forward-biased PN junction diode, the sequence of events that best describes the mechanism of current flow is

Diffusion capacitance of PN Junction Diode ______.

A Zener diode:(a) has a sharp breakdown at a low forward voltage(b) has a sharp breakdown at a low reverse voltage(c) can be used for voltage regulation(d) has a negative resistance regionCode:

In mercury arc rectifier, mercury is used as

Ionization within a P-N junction causes a layer on each side of the barrier called the

A tunnel diode is

Match the two lists and choose the correct answer from the code given below:List IList II(a) Foster Seeley discriminator(i) Optical fiber(b) Envelope detector(ii) Microwave(c) APD detector(iii) AM wave(d) PIN detector(iv) FM signal

A forward biased PN junction will acts as a/an:

In forward blocking region of SCR which of the following statements is correct?

Choose the INCORRECT statement with regard to a forward biased pn diode.

For a PN junction diode, width of space charge region increases as?

Find the reverse saturation current at 35° C for a junction which has I0 = 30 nA at 25° C.

Consider two infinite duration input sequences {x1[n], x2[n]}. When will the Region of Convergence [ROC] of Z-transform of their superposition i.e. {x1[n] + x2[n]} be entire Z plane except possibly at Z = 0 or Z = ∞ ?

A region of negative differential resistance is observed in the current voltage characteristics of a silicon PN junction if

An ideal diode is:

During the forward biased condition in a diode, the ratio of power dissipated in it to the forward DC current is known as:

Depletion layer is found in

Diffusion capacitance of a PN junction diode ________ with forward bias.

A reverse biased PN junction will act as a/an:

Assertion (A): The reverse saturation current approximately doubles for every 10°C temperature rise for both Si and Ge materials.Reason (R): At room temperature, the p-n junction voltage decreases by about 2.5 mV per °C rise in temperature.

It is possible to measure the voltage across the potential barrier through a voltmeter?

When the diode is reverse biased with a voltage of 6V and Vbi=0.63V. Calculate the total potential.

What is the maximum electric field when Vbi=2V , VR=5V and width of the semiconductor is 7cm?

During the reverse biased of the diode, the back resistance decrease with the increase of the temperature. Is it true or false?

If the voltage of the potential barrier is V0. A voltage V is applied to the input, at what moment will the barrier disappear?

During reverse bias, a small current develops known as

If the positive terminal of the battery is connected to the anode of the diode, then it is known as

How many junction/s do a diode consist?

is the maximum reverse voltage that can be applied to the pn junction to the junction.

During reverse bias operation of a PN junction, a feeble current flow known as which is __ barrier voltage.

When the diode is reverse biased with a voltage of 6V and V_bi=0.63V. Calculate the total potential.

What is the maximum electric field when V_bi=2V , V_R=5V and width of the semiconductor is 7cm?

If the voltage of the potential barrier is V₀. A voltage V is applied to the input, at what moment will the barrier disappear?