Free Electronics MCQs with Answers
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A p-n junction forms when p-type and n-type semiconductor regions meet, creating a depletion layer, barrier potential and rectifying action. The work covers forward and reverse bias, junction current, diode characteristics, and how a diode converts alternating current into pulsating direct current through half-wave and full-wave rectification.
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Read the Electronics notesFree MDCAT chapter notes with key terms660 questions · page 23 of 33
- A. Majority carriers
- B. Minority carriers
- C. Electrons
- D. Holes
Explanation: The reverse current in a semiconductor diode occurs when the diode is under reverse bias, meaning the voltage across the diode is applied…
Correct answer: Minority carriers- A. A.C into D.C
- B. D.C into A.C
- C. Both A.C into D.C and D.C into A.C
- D. None of these
Explanation: Rectification refers to the process of converting alternating current (A.C) into direct current (D.C).A diode is commonly used in…
Correct answer: A.C into D.C- A. The negative half cycle of input AC only
- B. The positive half cycle of input AC only
- C. The negative and positive half cycles of input AC
- D. None of these
Explanation: In half-wave rectification, the output DC voltage is obtained only during one half of the input AC cycle.During half-wave…
Correct answer: The positive half cycle of input AC only- A. Gallium
- B. Indium
- C. Boron
- D. None of these
Explanation: In semiconductor physics, impurities are classified as either donor or acceptor based on the type of charge carriers they introduce.
Correct answer: Indium- A. Increases
- B. Decreases
- C. Remains constant
- D. Some times decreases and sometimes increases
Explanation: With the rise in temperature, the conductivity of a pure semiconductor generally increases.Intrinsic semiconductors, those without any…
Correct answer: Increases- A. Full wave rectified
- B. No rectification and has the same peak value in the positive and negative half cycles
- C. No rectification and has different peak values during positive and negative half cycle
- D. Half wave rectified
Explanation: Direction of current is opposite through R for positive and negative half cycles so output is not rectified. Since R1 and R2 are same.
Correct answer: No rectification and has the same peak value in the positive and negative half cycles- A. A detector
- B. An oscillator
- C. An amplifier
- D. A rectifier
Explanation: The device used for the conversion of AC (alternating current) into DC (direct current) is called a rectifier.Rectifiers are electrical…
Correct answer: A rectifier- A. OR gate
- B. XOR gate
- C. AND gate
- D. NAND gate
Explanation: Option d is correct because we know that a combination of a NOT gate and an AND gate is known as a NAND gate, and since the given symbol…
Correct answer: NAND gate- A. Number of electrons increases while that of holes decreases.
- B. Number of holes increases while that of electrons decreases.
- C. Number of electrons and holes remains same
- D. Number of electrons and holes increases equally
Explanation: When an N-type semiconductor is heated, some electrons gain thermal energy, allowing them to move freely.
Correct answer: Number of electrons and holes increases equally- A. If both Assertion & Reason are true and the reason is the correct explanation of the assertion.
- B. If both Assertion & Reason are true but the reason is not the correct explanation of the assertion.
- C. If Assertion is true statement but Reason is false.
- D. If both Assertion and Reason are false statements.
Explanation: In n-type semiconductor electrons are the majority charge carriers and holes are minority charge carriers and n-type semiconductor is…
Correct answer: If both Assertion & Reason are true but the reason is not the correct explanation of the assertion.- A. At absolute zero temperature, the conduction band of semiconductor is completely filled and valance band is totally empty
- B. At absolute zero temperature, the conduction band of semiconductor is totally empty and valance band is totally filled
- C. At absolute zero temperature, both conduction band and valance band of semiconductor are totally empty
- D. At absolute zero temperature, both conduction band and valance band of semiconductor are completely filled
Explanation: The valence band is fully filled and the conduction band is completely empty at T = 0 K because it is the semiconductor's identity that it…
Correct answer: At absolute zero temperature, the conduction band of semiconductor is totally empty and valance band is totally filled- A. 20µA
- B. 26µA
- C. 30µA
- D. 35µA
Explanation: α = 0.96 β = α / 1 - α ==> 0.96 / 1 - 0.96 = 24 Ic = Vc / Rc Ic = 0.5 / 800 = 6.25 x 10-4 β = Ic / Ib Ib (base current) = 6.25 x 10-4 / 24…
Correct answer: 26µA- A. 15.114 mA
- B. 10.252 mA
- C. 2.606 mA
- D. 5.12 mA
Explanation: Δ IE = 8.86 mA Δ IC = 6.254 mA Δ IB + Δ IC = Δ IE Δ IB = Δ IE - Δ IC Δ IB = 8.86 - 6.254 Δ IB = 2.606 mA
Correct answer: 2.606 mA- A. It is used as Half wave rectifier
- B. It is used as shunt regulators
- C. It is used as ac voltage stabilizer
- D. none of these
Explanation: The Zener diode is used as a voltage stabilizer and as a shunt regulator.
Correct answer: It is used as Half wave rectifier- A. I
- B. II
- C. III
- D. IV
Explanation: Correct option is C) Current only flows from a higher potential to a lower potential.
Correct answer: III- A. Both depletion region and barrier height are reduced
- B. The depletion region is widened and barrier height is reduced
- C. Depletion region is reduced and barrier height is increased
- D. Both the depletion region and barrier height are increased
Explanation: When a p-n junction diode is forward-biased, both the depletion region and barrier height are reduced.
Correct answer: Both depletion region and barrier height are reduced- A. As rectifier
- B. For getting light radiation
- C. As amplifier
- D. For increasing the amplitude of a dc signal
Explanation: P-N junction diodes can be used as rectifiers, in photodiodes and LED
Correct answer: As amplifier- A. 30 Hz
- B. 60 Hz
- C. 120Hz
- D. 60/2πHz
Explanation: In full wave rectification pulse frequency (ripple frequency)=2xFrequency of source=2x60Hz=120Hz
Correct answer: 120Hz459. A germanium at 0K is
- A. Conductor
- B. Semiconductor
- C. Insulator
- D. P and N semiconductor
Explanation: When the temperature of semicondutors is increasing, their conductivity increases and when it is kept low so conductivity decreases.Thus…
Correct answer: Insulator- A. Bivalent
- B. Trivalent
- C. Tetravelent
- D. Pentavalent
Explanation: P-type are acceptor doping and trivalent whereas N-type are donor doping and pentavalent.
Correct answer: Trivalent