Free Electronics MCQs with Answers
660 Electronics MCQs from Physics, each with the correct answer and a written explanation of why it is correct. Free and unlimited, with no account needed.
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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- A. A
- B. B
- C. C
- D. D
Explanation: 1st circuit represents half-wave rectification and 2nd circuit represents filtered output with the help of capacitor and 3rd circuit…
Correct answer: B422. When an impurity is doped into an intrinsic semiconductor, the conductivity of the semiconductor:
- A. Increases
- B. Decreases
- C. Remains the same
- D. Becomes zero
Explanation: When an impurity is doped into an intrinsic semiconductor, it significantly alters the semiconductor's conductivity.
Correct answer: Increases423. Germanium at 0K is:
- A. Conductor
- B. Semiconductor
- C. Insulator
- D. P and N semiconductor
Explanation: Germanium is a semiconductor, which means that its ability to conduct electricity depends on the availability of free charge carriers.
Correct answer: Insulator- A. Boron
- B. Copper
- C. Indium
- D. Silicon
Explanation: Intrinsic semiconductors are pure forms of semiconductor materials. Silicon, being a group 4 element, can function as an intrinsic…
Correct answer: Silicon- A. 1:10-6
- B. 1:106
- C. 1:10-8
- D. 1:108
Explanation: In extrinsic semiconductors, achieving the right balance of dopant concentration is key to optimizing electrical properties.
Correct answer: 1:106- A. Bivalent
- B. Trivalent
- C. Tetravalent
- D. Pentavalent
Explanation: P-type semiconductors are created by doping silicon with trivalent elements, which have three valence electrons.
Correct answer: Trivalent- A. Resistor
- B. Capacitor
- C. Diode
- D. Triode
Explanation: When P-type and N-type semiconductors are combined, they form a PN junction, which is the fundamental building block of a diode.
Correct answer: Diode- A. Positively charged
- B. Negatively charged
- C. Both positively and negatively charged
- D. No mobile charge carriers
Explanation: The correct option is (d) No mobile charge carriers. The depletion region in a PN-junction is characterized by the absence of mobile…
Correct answer: No mobile charge carriers- A. 0.3 V
- B. 0.5 V
- C. 0.7 V
- D. 0.9 V
Explanation: The correct answer is C. The typical forward voltage drop for a silicon PN-junction is around 0.7 V.
Correct answer: 0.7 V- A. Decreases
- B. Increases
- C. Diode is forward biased, the width of the depletion region increases
- D. None of these
Explanation: When the P-type is connected to the negative and the N-type is connected to the positive, the diode is reverse-biased, and the width of…
Correct answer: Increases- A. 0.3 V
- B. 0.7 V
- C. 3 V
- D. 7 V
Explanation: The correct answer is Option A: 0.3 V. Germanium PN-junction diodes have a typical knee voltage of about 0.3 V when forward biased.
Correct answer: 0.3 V- A. Electrons are the majority carriers and trivalent atoms are the dopants
- B. Electrons are minority carriers and pentavalent atoms are the dopants
- C. Holes are minority carriers and pentavalent atoms are the dopants
- D. Holes are majority carriers and trivalent atoms are the dopants.
Explanation: In N-type silicon, pentavalent atoms such as phosphorus are used as dopants.
Correct answer: Holes are minority carriers and pentavalent atoms are the dopants- A. Majority carriers
- B. Acceptor ions
- C. Minority carriers
- D. Donor ions
Explanation: The reverse saturation current in a PN junction diode is largely due to the movement of minority carriers.
Correct answer: Minority carriers- A. Audible
- B. Compare
- C. Crystal diode
- D. Valence band
Explanation: Diodes are used for the rectification of electromagnetic waves. They convert alternating current (AC) into direct current (DC) by allowing…
Correct answer: Crystal diode- A. Majority carriers
- B. Minority carriers
- C. P-type
- D. N-type
Explanation: In a P-type semiconductor, the electrons generated due to thermal pair-generation are considered minority carriers.
Correct answer: Minority carriers- A. Four
- B. Three
- C. Two
- D. Nine
Explanation: There are two main types of rectifiers: half-wave rectifiers and full-wave rectifiers.
Correct answer: Two- A. Two
- B. One
- C. Three
- D. Five
Explanation: In a full-wave rectifier, either two diodes or four diodes can be used depending on the specific configuration.
Correct answer: Two- A. Negative
- B. One way conduction
- C. Two way conduction
- D. None of these
Explanation: "One-way conduction" refers to the property of a diode or semiconductor device that allows the flow of electrical current in only one…
Correct answer: One way conduction- A. Doping of p-materials
- B. Doping of n-materials
- C. Doping of both the p and n-materials
- D. None of these
Explanation: The width of the depletion region in a PN junction primarily depends on the doping concentrations of the P-type and N-type semiconductor…
Correct answer: Doping of both the p and n-materials- A. Increases
- B. Decreases
- C. Remains the same
- D. None of these
Explanation: When a PN junction is forward biased, the width of the depletion region decreases.In a forward-biased PN junction:The positive terminal of…
Correct answer: Decreases