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 6 of 6
- A. Reversed biased
- B. Forward biased
- C. Neutral
- D. None of these
Explanation: In a transistor, the emitter to base function is forward-biased. A transistor is a three-terminal semiconductor device that can amplify or…
Correct answer: Forward biased- A. Amplification
- B. Biasing
- C. Modulation
- D. Doping
Explanation: Biasing is the application of DC voltage to set up certain operating conditions.
Correct answer: Biasing- A. forward voltage
- B. reverse current
- C. forward current
- D. type of semiconductor
Explanation: LEDs are semiconductors that convert electrical energy into light energy.
Correct answer: type of semiconductor- A. NAND gate
- B. NOR gate
- C. OR gate
- D. XOR gate
Explanation: A NAND gate is a combination of AND and NOT gates. Option 'A' corresponds to the statement of the question.
Correct answer: NAND gate- A. Current gain
- B. Voltage gain
- C. Open-loop gain
- D. Closed-loop gain
Explanation: The correct answer is Voltage gain. It is defined as the ratio of the output voltage (V0) to the input voltage difference (Vin), which…
Correct answer: Voltage gain- A. Solar cell
- B. Photodiode
- C. Vacuum diode
- D. Light emitting diode
Explanation: The correct answer is the Light Emitting Diode (LED). LEDs are specifically designed to emit light when an electric current passes through…
Correct answer: Light emitting diode- A. Protons
- B. Electrons only
- C. Holes only
- D. Both electrons and holes
Explanation: In semiconductors, current is generated by the movement of charge carriers: electrons and holes.
Correct answer: Both electrons and holes- A. AC only
- B. DC only
- C. Both AC and DC
- D. None of them
Explanation: An operational amplifier is a very high gain voltage amplifier. It is used to amplify the signals by increasing its magnitude and can…
Correct answer: Both AC and DC- A. Holes
- B. Electrons
- C. Protons
- D. Positive ions
Explanation: Minority charge carriers are those charge-carrying units in a substance that are very few in quantity.
Correct answer: Electrons- A. The electric potential vanishes everywhere
- B. The electric field vanishes everywhere
- C. The diffusion current vanishes everywhere
- D. The diffusion and drift currents cancel each other
Explanation: A p-n junction is a boundary between two types of semiconductor materials, p-type and n-type.
Correct answer: The diffusion and drift currents cancel each other- A. Trivalent impurity
- B. Pentavalent impurity
- C. Pentavalent or trivalent impurities
- D. None of the above
Explanation: Intrinsic semiconductors, like silicon (Si) and germanium (Ge), have equal numbers of electrons and holes.
Correct answer: Pentavalent or trivalent impurities- A. N-type
- B. P-type
- C. Conductor
- D. All of the above
Explanation: In the p-type semiconductor, where there is a deficit of electrons, holes (positively charged vacancies) are the minority carriers.
Correct answer: P-type- A. Avatanche effect
- B. Break down of a diode
- C. Rectification
- D. Negative curent
Explanation: When a large current starts to flow in a reverse biased diode, it is known as the "avatanche effect." This happens when the reverse…
Correct answer: Avatanche effect- A. Emitter
- B. Base
- C. Collector
- D. Anyone can be heavily doped
Explanation: The heavily doped region is called the emitter. It plays a crucial role in the operation of the transistor by emitting majority charge…
Correct answer: Emitter- A. Capacitor
- B. ON switch
- C. Inductor
- D. OFF Switch
Explanation: When a PN junction is reverse biased, it acts like an insulator or an OFF switch.
Correct answer: OFF Switch