Free Electronics and Devices MCQs with Answers
758 Electronics and Devices MCQs from Electrical Engineering, each with the correct answer and a written explanation of why it is correct. Free and unlimited, with no account needed.
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758 questions · page 38 of 38
- A. carbon
- B. aluminium
- C. tungsten
- D. nickel
Explanation: Tungsten is used for incandescent bulb filaments because it has a very high melting point and can withstand intense heating while emitting…
Correct answer: tungsten- A. equal to the atomic number of the atom
- B. equal to the charge of an electron
- C. equal to the charge of the number of electrons in an atom (#) zero
Explanation: Ion charge is quantized in integral multiples of the elementary charge, so the smallest nonzero magnitude equals the charge of one…
Correct answer: equal to the charge of an electron- A. insulators
- B. non-linear resistors
- C. carbon resistors
- D. resistors with zero temperature coefficient
Explanation: A varistor is a voltage-dependent resistor whose resistance changes nonlinearly with applied voltage.
Correct answer: non-linear resistors- A. Aluminium
- B. Paper
- C. Rubber
- D. Mica
Explanation: Aluminium is a metal and its resistance generally increases with temperature, giving it a positive temperature coefficient.
Correct answer: Aluminium- A. metallic resistor
- B. carbon resistor
- C. wire wound resistor
- D. variable resistor
Explanation: A 10 ohm, 10 watt resistor must dissipate substantial power, for which wire-wound construction is more suitable than a typical carbon…
Correct answer: wire wound resistor- A. Iron
- B. Silver
- C. Copper
- D. Carbon
Explanation: Silver has the lowest resistivity among the listed materials, making it the best electrical conductor.
Correct answer: Silver- A. decreases
- B. increases
- C. first increases and then decreases
- D. remains constant
Explanation: In semiconductors, increasing temperature generates more charge carriers, so conductivity rises and resistance falls.
Correct answer: decreases- A. Metal - oxide semiconductor field effect transistor
- B. Molybdenum - oxide semiconductor field effect transistor
- C. Metal - oxide silicon field effect transistor
- D. Metal - oxide semiconductor field effect transmitter
Explanation: MOSFET expands to Metal-Oxide-Semiconductor Field-Effect Transistor. The device is controlled by an electric field at its insulated gate…
Correct answer: Metal - oxide semiconductor field effect transistor- A. Only minority carriers
- B. Only majority carriers
- C. Both minority and majority carriers
- D. None of these
Explanation: A MOSFET is a unipolar device: conduction is mainly by majority carriers, such as electrons in an n-channel MOSFET or holes in a p-channel…
Correct answer: Only majority carriers- A. Susceptibility
- B. Emission
- C. Interference
- D. Electromagnetic compatibility
Explanation: Electromagnetic compatibility means equipment can operate correctly in its electromagnetic environment without creating unacceptable…
Correct answer: Electromagnetic compatibility- A. Immunity
- B. Emission
- C. Interference
- D. Electromagnetic compatibility
Explanation: Susceptibility is the tendency of equipment to be disturbed by electromagnetic interference, while immunity is its ability to withstand…
Correct answer: Immunity- A. Unidirectional
- B. Bidirectional
- C. Fixed voltage polarity
- D. Only (a) and (c)
Explanation: An ideal diode permits current in only one direction and blocks it in the reverse direction, so it is unidirectional.
Correct answer: Only (a) and (c)- A. Motors
- B. Switches, radio interferences
- C. Computers, digital electronics
- D. All of these
Explanation: Motors, switching circuits, radio interference, computers, and digital electronics can all generate electromagnetic noise through…
Correct answer: All of these754. Any electrical signal present in a circuit other than the desired signal is known as______________?
- A. Noise
- B. Distortion
- C. Interference
- D. All of these
Explanation: Noise is any unwanted electrical signal superimposed on the desired signal.
Correct answer: Noise- A. Decays as 1 / R, where R is the separation distance between the emitter and the receptor
- B. Decays as R, where R is the separation distance between the emitter and the receptor
- C. Decays as 1 / 2 R, where R is the separation distance between the emitter and the receptor
- D. Decays as 2R, where R is the separation distance between the emitter and the receptor
Explanation: In the far-field region, the radiated electric and magnetic field amplitudes spread spherically and decrease inversely with distance, as…
Correct answer: Decays as 1 / R, where R is the separation distance between the emitter and the receptor- A. Do not contribute to the collector current
- B. Result in net current flow component into the base
- C. Contribute to the collector current
- D. Only (a) and (b)
- E. Only (b) and (c)
Explanation: Holes injected from the base into the emitter produce a base-current component, but they normally do not contribute to collector current.
Correct answer: Only (a) and (b)757. The output power of the cascaded amplifier / attenuator system can be determined using___________?
- A. Actual gain of amplifier
- B. Actual gain of amplifier and attenuator
- C. Gain in dB of amplifier and attenuator
- D. Actual gain of attenuator
Explanation: For cascaded stages, the total actual voltage or power gain is found by multiplying the amplifier gain by the attenuator’s transmission…
Correct answer: Actual gain of amplifier and attenuator- A. Kq/T
- B. KT/q
- C. qT/K
- D. (K2/q)(T + 1/T - 1)
Explanation: Thermal voltage is obtained from the energy-to-voltage relation, giving V_T = kT/q, where k is Boltzmann's constant, T is absolute…
Correct answer: KT/q