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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Read the Electronics notesFree MDCAT chapter notes with key terms660 questions · page 12 of 33
- A. Power amplifier
- B. Current amplifier
- C. Voltage amplifier
- D. None of these
Explanation: A current amplifier, an electronic circuit that is used to magnify or increase the magnitude of the current, keeping the voltage component…
Correct answer: Current amplifier- A. Oscillator
- B. Switches
- C. Units
- D. All of above
Explanation: A transistor can act as a switch or gate for electronic signals, opening and closing an electronic gate many times per second.
Correct answer: All of above- A. The collector-base junction is forward biased and the collector-base junction is reverse biased
- B. Both the junction are farward biased
- C. Both the junction are reverse biased
- D. None of these
Explanation: So, Transistor to be used as an amplifier,Emitter-base junction must be reverse biased, Collector-base junction must be forward biased.
Correct answer: The collector-base junction is forward biased and the collector-base junction is reverse biased- A. Temperature dependent
- B. Sound dependent
- C. Energy dependent
- D. Light dependent
Explanation: As temperature increases, the thermal runaway property of a transistor becomes more prominent, since transistors have negative coefficient…
Correct answer: Temperature dependent- A. Forward biased
- B. Reverse biased
- C. Both forward and reverse
- D. None of these
Explanation: In baseemitter transistors the current is flowing forward biased, whereas, in collector and emitter transistors the current is passing in…
Correct answer: Forward biased- A. Inductor
- B. Capacitor
- C. Transistor
- D. P-n junction
Explanation: .A p-n junction diode can work as an excellent rectifier since it offers a low resistance for the current to flow when it is forward…
Correct answer: P-n junction- A. Photo diode
- B. Light emitting diode
- C. Photo-voltaic cell
- D. All of the above
Explanation: Photodiode, light emitting diode and photo voltaic cell are all examples of devices in which a p-n junction is used.
Correct answer: All of the above- A. Emission of energy in the form of photons
- B. Faraday's law
- C. Ionic bonding between p-type and n-type substances
- D. None of these
Explanation: A light-emitting diode is made from special semiconductors such as gallium arsenide and gallium arsenide phosphide in which the potential…
Correct answer: Emission of energy in the form of photons- A. An automatic ON and OFF switch
- B. Detection of light
- C. Logic gates
- D. All of above
Explanation: Applications of photodiode:i. Detection of both visible and invisible radiationii. Automatic switchingiii. Logic circuitsiv.
Correct answer: All of above- A. Base
- B. Collector
- C. Emitter
- D. None of above
Explanation: A transistor consists of a single crystal of germanium or silicon which is grown in such a way that it has three regions.
Correct answer: Base- A. n-n junction
- B. p-p junction
- C. n-p-n transistor
- D. p-n-p transistor
Explanation: An n-p-n transistor is one of the most common types of bipolar junction transistors (BJTs).
Correct answer: n-p-n transistor- A. IE = IC
- B. IE = lC + IB
- C. IE = IB
- D. None of these
Explanation: After the application of the biasing voltage to the transistor, the emitter-base junction is forward-biased, so the emitter injects a…
Correct answer: IE = lC + IB- A. 105
- B. 106
- C. 10-5
- D. 10-6
Explanation: The open-loop DC gain (usually referred to as AVOL and sometimes as forward gain) is the gain of the amplifier without the feedback loop…
Correct answer: 105- A. Capacitor
- B. Low resistor
- C. Inductor
- D. High resistor
Explanation: When forward-biased, a p-n junction allows a current of a few milliamperes to flow across it because there is sufficient energy to…
Correct answer: Low resistor- A. Constant
- B. Positive
- C. Negative
- D. Variable
Explanation: The temperature coefficient of resistance of a semiconductor is negative.
Correct answer: Negative- A. Silicon
- B. Copper
- C. Gallium arsenide
- D. Germinium
Explanation: Copper is a metal and all metals are conductors because they have free electrons.
Correct answer: Copper- A. Both XC and XL are doubled
- B. Both XC and XL are halved
- C. XC is doubled and XL reduces to half
- D. XL is doubled and XC reduces to half
- E. Both XC and XL are unchanged
Explanation: The inductive reactance of an inductor increases as the frequency across it increases therefore inductive reactance is proportional to…
Correct answer: XL is doubled and XC reduces to half- A. Reverse-biased junction diode
- B. Forward-biased junction diode
- C. Half wave rectifier
- D. Full wave rectifier
- E. Transistor
Explanation: The photodiode is reverse biased for operating in the photoconductive mode.
Correct answer: Reverse-biased junction diode- A. IC + IB
- B. IC - IB
- C. IC x IB
- D. Zero
Explanation: Emitting current=Collecting current+Base current.
Correct answer: IC + IB- A. Forward
- B. Resistance
- C. Reverse
- D. Converse
Explanation: The photodiode is reverse biased for operating in the photoconductive mode.
Correct answer: Reverse