CCommunications.website
Home

All Electronics & Telecommunication MCQs

Up to 100 questions are displayed per page.

Question 1
Digital ElectronicsLogic Gates

Which logic gate gives a HIGH output only when all its inputs are HIGH?

  • AOR gate
  • BNAND gate
  • CAND gate
  • DXOR gate
Report an error
Correct Answer: C. AND gate
Explanation: An AND gate produces logic HIGH only when all of its inputs are HIGH.
Reference: Standard digital electronics principle
Question 2
Digital ElectronicsNumber Systems

What is the binary equivalent of decimal number 10?

  • A1001
  • B1010
  • C1100
  • D1110
Report an error
Correct Answer: B. 1010
Explanation: Decimal 10 equals 8 + 2, which is 1010 in binary.
Reference: Binary number system fundamentals
Question 3
Analog ElectronicsOperational Amplifiers

For an ideal operational amplifier, the input impedance is assumed to be?

  • AZero
  • BInfinite
  • C1 ohm
  • DEqual to output impedance
Report an error
Correct Answer: B. Infinite
Explanation: An ideal op-amp draws zero input current; therefore its input impedance is considered infinite.
Reference: Ideal operational amplifier characteristics
Question 4
Network TheoryCircuit Laws

Kirchhoff’s Current Law is based on conservation of?

  • AEnergy
  • BCharge
  • CPower
  • DMomentum
Report an error
Correct Answer: B. Charge
Explanation: KCL follows conservation of electric charge: the algebraic sum of currents at a node is zero.
Reference: Kirchhoff's circuit laws
Question 5
Communication SystemsAnalog Modulation

In amplitude modulation, which carrier parameter is varied according to the message signal?

  • AFrequency
  • BPhase
  • CAmplitude
  • DWavelength only
Report an error
Correct Answer: C. Amplitude
Explanation: In conventional amplitude modulation, the amplitude of the carrier varies with the instantaneous message signal.
Reference: Amplitude modulation fundamentals
Question 6
Signals & SystemsSampling

According to the sampling theorem, a band-limited signal should be sampled at a rate of at least?

  • AHalf the highest signal frequency
  • BEqual to the highest signal frequency
  • CTwice the highest signal frequency
  • DFour times the lowest signal frequency
Report an error
Correct Answer: C. Twice the highest signal frequency
Explanation: For ideal reconstruction, the sampling frequency must be at least twice the highest frequency component of the band-limited signal.
Reference: Nyquist sampling theorem
Question 7
Power ElectronicsPower Semiconductor Devices

Which device is commonly used as a controlled switch in power-electronic circuits?

  • ASCR
  • BLDR
  • CZener diode only
  • DPhotodiode
Report an error
Correct Answer: A. SCR
Explanation: An SCR is a thyristor widely used as a controlled switching device in power-electronic converters.
Reference: Power electronics fundamentals
Question 8
Microprocessors & Microcontrollers8085 Microprocessor

The 8085 microprocessor has an address bus of how many bits?

  • A8 bits
  • B12 bits
  • C16 bits
  • D32 bits
Report an error
Correct Answer: C. 16 bits
Explanation: The 8085 has a 16-bit address bus, allowing it to address 2^16 or 64 KB of memory locations.
Reference: 8085 architecture
Question 9
Measurements & InstrumentationElectronic Instruments

Which instrument is primarily used to display an electrical waveform versus time?

  • AAmmeter
  • BOscilloscope
  • CWattmeter
  • DMegger
Report an error
Correct Answer: B. Oscilloscope
Explanation: An oscilloscope displays voltage waveforms and commonly shows their variation with time.
Reference: Electronic measurement fundamentals
Question 10
Control SystemsStability

For a stable continuous-time linear system, poles of the closed-loop transfer function should generally lie in which region of the s-plane?

  • ARight half-plane
  • BLeft half-plane
  • COnly on the imaginary axis
  • DAt the origin only
Report an error
Correct Answer: B. Left half-plane
Explanation: For an asymptotically stable continuous-time LTI closed-loop system, its poles lie in the left half of the s-plane.
Reference: Classical control-system stability criterion