Electronic Devices And Circuits MCQ Questions & Answers

61

A silicon sample A is doped with 10¹⁸atoms/cm³ of Boron. Another sample B of identical dimensions is doped with 10¹⁸ atoms/cm³ of Phosphorus. The ratio of electron to hole mobility is 3. The ratio of conductivity of the sample A to B is

A) $$3$$ B) $$\frac{1}{3}$$ C) $$\frac{2}{3}$$ D) $$\frac{3}{2}$$

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Answer & Solution

Answer: Option B

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62

Which is the diode used for measuring light intensity?

A) Junction diode B) Varactor diode C) Tunnel diode D) Photodiode

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Answer & Solution

Answer: Option D

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63

The drift of a hole in a semiconductor is brought by-

A) The vacancy being filled by an ion B) The vacancy being filled by a valence electron from a neighbouring atoms C) The vacancy being filled by a free electron D) The movement of an atom in the solid

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Answer & Solution

Answer: Option B

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64

The width of the energy band depends on which of the following?

A) Temperature B) Pressure C) Relative freedom of electrons in the crystal D) Mass of atom in the material

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Answer & Solution

Answer: Option A

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65

Silicon is not suitable for fabrication of light emitting diodes because it is

A) An indirect bandgap semiconductor B) A direct bandgap semiconductor C) A wide bandgap semiconductor D) A narrow bandgap semiconductor

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Answer & Solution

Answer: Option A

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66

Bulk resistance of a diode is

A) sum of resistance values of n-material and p-material B) sum of half the resistance values of n-material and p-material C) equivalent resistance of the resistance value of p and n-material in parallel D) none of the above

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Answer & Solution

Answer: Option A

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67

Calculate the reverse resistance of a Si diode when the reverse voltage is 50 V and the current is 100 nA.

A) 500 MΩ B) 100 MΩ C) 50 MΩ D) 600 MΩ

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Answer & Solution

Answer: Option A

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68

The Fermi level in a p-type semiconductor lies close to

A) top of the valence band B) bottom of the valence band C) top of the conduction band D) bottom of the conduction band

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Answer & Solution

Answer: Option A

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69

Match List-I with List-II and select the correct answer using the options given below:

List-I (Type of Conductor)	List-II (Position of Fermi Level)
a. n-type semiconductor	1. Middle of band gap
b. p-type semiconductor	2. Above conduction band
c. Intrinsic semiconductor	3. Near but below conduction band
d. Degenerate n-type semiconductor	4. Near but above valence band

A) a-1, b-2, c-3, d-4 B) a-3, b-4, c-1, d-2 C) a-1, b-4, c-3, d-2 D) a-3, b-2, c-1, d-4

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Answer & Solution

Answer: Option B

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70

A good ohmic contact on P-type semiconductor chip is formed by introducing

A) gold as an impurity below the contact B) a high concentration of donors below the contact C) a high concentration of acceptors below the contact D) a thin insulator layer between the metal and semiconductor

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Answer & Solution

Answer: Option B

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Electronic Devices And Circuits MCQ Questions & Answers | ECE