25 Important MCQ On Diode(Read This First!)

1.  A Varactor Diode performs as

1. A variable resistor
2. A variable capacitor
3. A switching device
4. none of these

Answer – (2)

2.  When PN junction diode is forward bias, forward current is dominated by

1. The diffusion current
2. The displacement current
3. The drift current
4. The drift or diffusion current

Answer – (1)

3.  Storage capacitance in the PN junction is due to

1. The majority carriers
2. The minority carriers
3. The majority and the minority carriers, equally
4. None of these

Answer – (3)

4. A varicap is worked in

• The reverse biasing condition
• The forward biasing condition
• Without biasing condition
• None of these

Answer – (1)

5.   Which has -ve resistance region of operation?

1. The Zener type
2. The Tunnel type
3. The photodiode
4. The LED

Answer – (2)

6.   IMPATT diode is

1. A negative conductance microwave device
2. A high frequency rectifying device
3. A degenerate semiconductor device
4. A bulk negative differential conductance device

Answer – (1)

7.   Operation of Gunn diode is explained with

1. The transferred electrons effect
2. The avalanche transmit time effect
3. The tunneling effect
4. The Schottky effect

Answer  – (3)

8.   Tunnel Diode is employed in

1. The Micro-wave Oscillator design
2. The RF Oscillator design
3. An audio oscillator design
4. A Video amplifier design

Answer – ( 3 )

9.   Reverse saturation current of the PN junction diode is working as

1. The diffusion current
2. The drift current
3. The displacement current
4. None of these

Answer – (2)

10.    I is PN junction diode forward current. Diffusion capacitance is proportional to

1. I^1/2
2. I^3/2
3. I
4. I²

Answer – (1)

11.    Zener effect is operated at

1. high reverse voltage and for heavily doped junction
2. low reverse voltage and for heavily doped junction
3. high reverse voltage and for lightly doped junction
4. low reverse voltage and for lightly doped junction

Answer – (2)

12.    IMPATT diode works by the mechanism of

1. electron tunneling
2. transferred electrons
3. avalanche multiplication
4. none of these

Answer  – (1)

13.    The Schottky diode is used in high speed operation because of

1. small current potential
2. high speed of electrons
3. small size
4. insignificant storage delay

Answer – (2)

14.    Gun diode is utilized in

1. The microwave oscillator
2. The RF oscillator
3. An audio oscillator
4. An audio amplifier

Answer – (1)

15.    Zener diodes are

1. specially doped PN junction
2. normally doped PN junction
3. lightly doped PN junction
4. none of these

Answer – (1)

16.    Diffusion current in a PN junction is influenced by

1. concentration gradient of carriers
2. applied voltage
3. concentration of carriers
4. none of these

Answer – (1)

17.    If a voltage (+ve.) is connected to an n-type semiconductor through the metal plate, the barrier in between

1. Will increases
2. Will decreases
3. Will remains same
4. none of these, will happen

Answer – (1)

18. We can connect photodetector diode in

1. both in forward bias and reverse bias
2. forward bias
3. reverse bias
4. no need to connect any bias

Answer – (3 )

19.    In photodiode, electron- hole pairs are engendered, if

1. The energy of incident photon (hf) < Eg
2. The energy of incident photon  (hf)> Eg
3. The energy of incident photon (hf) = Eg
4. The energy of incident photon  (hf) >> Eg

Answer – (2)

20. Solar cell works in

• I-Quadrant
• IV-Quadrant
• II-Quadrant
• III-Quadrant

Answer – (2)

21.    Avalanche breakdown primarily be influenced by the phenomenon of

1. The impact ionization
2. The field ionization
3. The particle collision
4. The impurity doping

Answer – (1)

22.    The Solar Cell’s V-I plot Quadrant will be at

1. I
2. II
3. III
4. IV

Answer – (4)

23.    Which of the following type does not possess a negative resistance region in its characteristics?

1. The Tunnel type
2. The Gun type
3. The Zener type
4. The IMPATT type

Answer – (3)

24.    What will be the reading of voltmeter, if it is connected using an unbiased Germanium PN junction diode?

1. 0 Volt
2. 0.3 Volt
3. 0.6 Volt
4. 1.0 Volt

Answer – (1)

25.    Photodetector is following

1. triangular device
2. square law device
3. linear device
4. both a & b

Answer – ( 3 )

26.    LED works on the principle of

1. photoluminescence
2. electroluminescence
3. cathodoluminescence
4. radioluminescence

Answer – (1)

27.    PIN diode has

1. p and n layers separated by 1 layer
2. p+ and n+ layers separated by 1 layer
3. p- and n- layers separated by 1 layer
4. either b or c

Answer – (2)

28.    A voltage variable capacitance can be realized in

1. The Avalanche type
2. The Zener type
3. The Schottky type
4. The Varicap or varactor type

Answer – (4)

29.    In a voltage regulator circuit, the maximum value

1. 2.5 mA load current
2. 0.9 mA load current
3. 1.6 mA load current
4. 3.4 mA load current

Answer – (4)

30.    The Varicap are ordinarily used

1. As a voltage controlled capacitance circuitry
2. as a constant current source
3. as a voltage multiplier circuitry
4. as a constant voltage source

Answer – (1)

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