Semiconductor Devices MCQs

1. What is the majority charge carrier in an N-type semiconductor?
A. Holes
B. Electrons
C. Ions
D. Protons
Answer: B. Electrons

2. Which of the following is a P-N junction diode?
A. BJT
B. FET
C. LED
D. Zener diode
Answer: C. LED

3. The process of adding impurities to a semiconductor to increase its conductivity is called:
A. Purification
B. Doping
C. Polishing
D. Refining
Answer: B. Doping

4. A Zener diode operates in:
A. Forward bias
B. Reverse bias
C. Cut-off region
D. Saturation region
Answer: B. Reverse bias

5. The breakdown in a Zener diode occurs due to:
A. Avalanche effect
B. Thermal effect
C. Voltage reversal
D. Forward bias
Answer: A. Avalanche effect

6. A Schottky diode is known for:
A. High reverse leakage current
B. Low forward voltage drop
C. High breakdown voltage
D. Low temperature coefficient
Answer: B. Low forward voltage drop

7. Which semiconductor device has a negative resistance characteristic?
A. Bipolar Junction Transistor (BJT)
B. Schottky diode
C. Tunnel diode
D. Varactor diode
Answer: C. Tunnel diode

8. The term ‘mobility’ in semiconductor physics refers to:
A. Ease of doping
B. Rate of electron-hole recombination
C. Ability of charge carriers to move in response to an electric field
D. Temperature coefficient of resistance
Answer: C. Ability of charge carriers to move in response to an electric field

9. Which of the following devices can amplify signals?
A. Zener diode
B. LED
C. BJT
D. Varactor diode
Answer: C. BJT

10. In a JFET, the channel conductivity is controlled by:
A. Gate-source voltage
B. Drain-source voltage
C. Drain-gate voltage
D. Gate-drain voltage
Answer: A. Gate-source voltage

11. A thyristor is commonly used as:
A. Rectifier
B. Voltage regulator
C. Switch
D. Oscillator
Answer: C. Switch

12. Which of the following is NOT a type of thyristor?
A. Triac
B. Diac
C. SCR
D. BJT
Answer: D. BJT

13. Which material is commonly used as a semiconductor in solar cells?
A. Silicon
B. Copper
C. Aluminum
D. Silver
Answer: A. Silicon

14. The term ‘bandgap’ in semiconductors refers to:
A. The energy difference between the valence band and the conduction band
B. The energy difference between N-type and P-type regions
C. The energy difference between electrons and holes
D. The energy difference between forward and reverse biasing
Answer: A. The energy difference between the valence band and the conduction band

15. A photodiode is used for converting:
A. Light into current
B. Current into light
C. Voltage into current
D. Voltage into light
Answer: A. Light into current

16. Which of the following is a passive semiconductor component?
A. Diode
B. Transistor
C. Capacitor
D. Thyristor
Answer: C. Capacitor

17. In an NPN transistor, the majority carriers in the base region are:
A. Holes
B. Electrons
C. Ions
D. Protons
Answer: A. Holes

18. The reverse breakdown voltage of a Zener diode is mainly dependent on:
A. Forward current
B. Reverse current
C. Junction temperature
D. Dopant concentration
Answer: D. Dopant concentration

19. A Varactor diode is primarily used for:
A. Rectification
B. Amplification
C. Voltage-controlled capacitance
D. Voltage regulation
Answer: C. Voltage-controlled capacitance

20. Which of the following is an application of a tunnel diode?
A. Power rectification
B. High-frequency oscillation
C. Voltage regulation
D. Current amplification
Answer: B. High-frequency oscillation

21. The process of forming a P-N junction by diffusion is called:
A. Bonding
B. Oxidation
C. Ionization
D. Alloying
Answer: B. Oxidation

22. Which of the following diodes is used in voltage regulators?
A. Zener diode
B. Schottky diode
C. LED
D. Tunnel diode
Answer: A. Zener diode

23. A thyristor remains in the conducting state until:
A. The gate voltage is applied
B. The anode current is zero
C. The gate voltage is removed
D. The anode current exceeds a threshold
Answer: B. The anode current is zero

24. The primary purpose of a transistor in electronic circuits is to:
A. Control current
B. Store charge
C. Generate light
D. Store energy
Answer: A. Control current

25. Which semiconductor device is used for signal switching and amplification?
A. Photodiode
B. BJT
C. Varactor diode
D. Thyristor
Answer: B. BJT

26. The depletion region in a P-N junction contains:
A. Free electrons
B. Positive ions
C. Negative ions
D. Holes
Answer: C. Negative ions

27. Which diode is used for rectification purposes?
A. Zener diode
B. Tunnel diode
C. Schottky diode
D. LED
Answer: C. Schottky diode

28. A JFET has a channel that is:
A. P-type
B. N-type
C. Intrinsic
D. Extrinsic
Answer: B. N-type

29. Which of the following devices has three terminals?
A. Diode
B. SCR
C. Tunnel diode
D. Photodiode
Answer: B. SCR

30. A MOSFET is primarily used for:
A. Voltage regulation
B. High-frequency oscillation
C. Signal amplification
D. Switching applications
Answer: D. Switching applications

31. The breakdown voltage of a diode is approximately:
A. 0.3V
B. 0.7V
C. 1.1V
D. 1.5V
Answer: B. 0.7V

32. Which semiconductor device has a negative temperature coefficient of resistance?
A. Zener diode
B. Thermistor
C. Schottky diode
D. Photodiode
Answer: B. Thermistor

33. The term ‘cut-off’ in a semiconductor device refers to:
A. The condition when the device is not conducting
B. The maximum current rating
C. The breakdown voltage
D. The reverse bias condition
Answer: A. The condition when the device is not conducting

34. A photovoltaic cell converts:
A. Light into heat
B. Light into electricity
C. Heat into electricity
D. Electricity into light
Answer: B. Light into electricity

35. Which diode has the fastest switching speed?
A. Zener diode
B. Schottky diode
C. LED
D. Tunnel diode
Answer: D. Tunnel diode

36. Which of the following is a characteristic of a Schottky diode?
A. High reverse leakage current
B. High forward voltage drop
C. High breakdown voltage
D. Low temperature coefficient
Answer: B. High forward voltage drop

37. In a P-type semiconductor, the majority charge carriers are:
A. Electrons
B. Holes
C. Ions
D. Protons
Answer: B. Holes

38. Which semiconductor device is commonly used as a rectifier?
A. BJT
B. FET
C. Diode
D. SCR
Answer: C. Diode

39. The gate of a MOSFET is made of:
A. P-type semiconductor
B. N-type semiconductor
C. Metal
D. Silicon dioxide
Answer: C. Metal

40. Which of the following is NOT a type of diode?
A. Zener diode
B. Tunnel diode
C. FET
D. LED
Answer: C. FET

41. A bipolar junction transistor consists of:
A. One P-type and two N-type layers
B. Two P-type and one N-type layers
C. One P-type and one N-type layer
D. Two N-type and one P-type layers
Answer: B. Two P-type and one N-type layers

42. The reverse leakage current in a diode primarily depends on:
A. Forward voltage
B. Reverse voltage
C. Temperature
D. Light intensity
Answer: C. Temperature

43. A Zener diode is used primarily for:
A. Rectification
B. Amplification
C. Voltage regulation
D. Current control
Answer: C. Voltage regulation

44. Which of the following is a characteristic of an LED?
A. Low forward voltage drop
B. High reverse leakage current
C. High breakdown voltage
D. Negative resistance
Answer: A. Low forward voltage drop

45. The current gain in a BJT is denoted by:
A. β
B. α
C. γ
D. δ
Answer: A. β

46. A Varactor diode is used primarily in:
A. Power supplies
B. Oscillators
C. Voltage regulators
D. Switching circuits
Answer: B. Oscillators

47. Which semiconductor device has the highest input impedance?
A. BJT
B. FET
C. Diode
D. Thyristor
Answer: B. FET

48. A diode operates as an open circuit in which biasing condition?
A. Forward bias
B. Reverse bias
C. Zero bias
D. Cut-off bias
Answer: B. Reverse bias

49. The threshold voltage of a MOSFET refers to:
A. The voltage below which the device does not conduct
B. The voltage above which the device conducts
C. The voltage at which breakdown occurs
D. The voltage at which reverse biasing occurs
Answer: A. The voltage below which the device does not conduct

50. Which of the following devices is used for switching high-power circuits?
A. Diode
B. SCR
C. Varactor diode
D. Photodiode
Answer: B. SCR

Semiconductor Devices MCQs

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