Free PN Junction MCQs with Answers
115 PN Junction 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 PN junction forms when p type and n type semiconductor regions meet, creating a depletion layer and a potential barrier. The topic covers forward and reverse bias, diode current voltage characteristics, breakdown and rectification, while distinguishing an ordinary junction diode from a transistor formed from multiple junctions.
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115 questions · page 5 of 6
- A. Diode.
- B. Buffer.
- C. Resistor.
- D. Resistor-transistor.
Explanation: The correct answer is a diode. Diodes are semiconductor devices that allow current to flow in one direction only, acting as a one-way…
Correct answer: Diode.- A. Holes.
- B. Protons.
- C. Positrons.
- D. Electrons.
Explanation: In an n-type semiconductor, the material is doped with donor atoms that have more valence electrons than the semiconductor material…
Correct answer: Electrons.- A. Voltage decreases.
- B. Voltage becomes zero.
- C. Diode resistance decreases.
- D. Diode's efficiency increases.
Explanation: In a reverse-biased junction, when the reverse current reaches its maximum value, it indicates that the diode has entered the breakdown…
Correct answer: Voltage decreases.- A. Zero.
- B. Widened.
- C. Narrowed.
- D. Unchanged.
Explanation: When a p-n junction is reverse biased, the electric field across the junction increases, causing the depletion region to widen.
Correct answer: Widened.- A. Ions.
- B. Holes.
- C. Electrons.
- D. Molecules.
Explanation: In an NPN transistor, the base is made of p-type material, where holes are the majority carriers.
Correct answer: Electrons.- A. 4
- B. 16
- C. 32
- D. 64
Explanation: This can be calculated using the formula 2n, where n is the number of possible inputs. The number of inputs is 4.
Correct answer: 16- A. Momentum
- B. Charge
- C. Mass
- D. All of these options are correct
Explanation: Solar cell devices are known to follow the 'photovoltaic effect', which is the conversion of sunlight to direct current.
Correct answer: Charge- A. NOR.
- B. XNOR.
- C. XOR.
- D. Both B and C.
Explanation: In logic gates, a NAND gate produces an output of 1 unless both inputs are 1. For inputs A=0 and B=1, the NAND gate outputs 1.
Correct answer: XOR.- A. High voltage.
- B. Photon.
- C. Hole.
- D. Positron.
Explanation: A hole or an electron hole is a point in an atom, a lattice or a structure where an electron can exist but does not because it has been…
Correct answer: Hole.- A. No
- B. Very large
- C. Few milliamperes
- D. Both A and C
Explanation: a) No: This option suggests that practically no current flows in a reverse p-n junction.
Correct answer: No- A. Indium
- B. Aluminium
- C. Arsenic
- D. Both B and C
Explanation: N- type semiconductor is denoted by positive ion and free electron.Silicon Si has 4 valence electrons and Arsenic As has 5 valence…
Correct answer: Arsenic- A. -1
- B. 10
- C. -10
- D. 1
Explanation: Explanation:The gain of an inverting amplifier using an operational amplifier is given by the ratio of the feedback resistor to the input…
Correct answer: -10- A. AND Gate
- B. XNOR Gate
- C. NAND Gate
- D. NOR Gate
Explanation: Explanation:If inputs A = 1, B = 0, and output X = 1, the it corresponds to the operation of a NAND Gate.
Correct answer: NAND Gate- A. 250
- B. 100
- C. 150
- D. 200
Explanation: Explanation: Collector currect: Ic = 10mA = 10 × 10-3 A Base current = IB = 50μA = 50 × 10-6 A Current gain = β = ?As we know that, β = Ic…
Correct answer: 200- A. 0°
- B. 270°
- C. 360°
- D. 180°
Explanation: Explanation:When an operational amplifier is used as an inverting amplifier, the output terminal with a phase shifted of 180°.
Correct answer: 180°- A. 10-5 cm
- B. 10-6 m
- C. 10-6 mm
- D. 10-6 µm
Explanation: The base region in a transistor is the central area that is lightly doped compared to the emitter and collector regions.
Correct answer: 10-6 m- A. Neutral (0)
- B. Positive
- C. Negative
- D. Variable
Explanation: An N-type semiconductor is doped with pentavalent elements, which introduce additional free electrons.
Correct answer: Neutral (0)98. The current gain of a transistor having a collector current of 10 mA and a base current of 40 A is:
- A. 2.5
- B. 25
- C. 250
- D. 2500
Explanation: Current gain is the ratio of the change in the collector current to the change in the emitter current in a transistor.
Correct answer: 250- A. Nonviolent
- B. Divalent
- C. Trivalent
- D. Pentavalent
Explanation: A p-type crystal is formed when a semiconductor crystal, such as Germanium (Ge) or Silicon (Si), is doped with an impurity that has one…
Correct answer: Trivalent- A. Vallage amplifier
- B. Oxillator
- C. Current amplifier
- D. Rectifier
Explanation: A Transistor is a device which consists of three regions of doped semiconductors in which the current flowing is modulated by the voltage…
Correct answer: Current amplifier