Electronics and communications. - Question Bank

1. What is the term for a signal whose amplitude varies continuously with time?
A) Digital signal
B) Analog signal
C) Square wave
D) Pulse signal
2. Which of the following is a semiconductor device that amplifies current?
A) Resistor
B) Capacitor
C) Transistor
D) Diode
3. What property of a conductor is measured in Ohms?
A) Conductance
B) Resistance
C) Capacitance
D) Inductance
4. What is the core function of a 'microprocessor'?
A) To store large amounts of data
B) To perform arithmetic and logic operations
C) To transmit signals over long distances
D) To convert analog signals to digital
5. Which type of wave is primarily used for satellite communication?
A) Infrared waves
B) Microwaves
C) Ultraviolet waves
D) X-rays
6. What is the term for the process of combining a message signal with a carrier wave?
A) Demodulation
B) Detection
C) Modulation
D) Multiplexing
7. Which electronic component acts like a variable resistor controlled by an electrical signal?
A) Diode
B) Transistor
C) Capacitor
D) Inductor
8. What is the purpose of a transformer?
A) To convert AC to DC
B) To change AC voltage levels
C) To amplify signals
D) To store electrical energy
9. What is the basic unit of digital information?
A) Byte
B) Word
C) Bit
D) Nibble
10. Which type of sensor converts light energy into electrical energy?
A) Thermistor
B) Photodiode
C) LDR (Light Dependent Resistor)
D) Both B and C
11. What is the term for the range of frequencies over which a communication system operates?
A) Bandwidth
B) Wavelength
C) Amplitude
D) Phase
12. What is the primary role of an operational amplifier (op-amp)?
A) To rectify signals
B) To amplify signals
C) To oscillate signals
D) To filter signals
13. Which component is used to measure voltage in a circuit?
A) Ammeter
B) Ohmmeter
C) Voltmeter
D) Galvanometer
14. What is the name of the phenomenon where a semiconductor device emits light when current flows through it?
A) Photovoltaic effect
B) Photoelectric effect
C) Electroluminescence
D) Thermoelectric effect
15. Which type of communication system uses light pulses to transmit information?
A) Coaxial cable
B) Twisted pair
C) Fiber optic
D) Radio wave
16. What is the term for the unwanted electrical energy that interferes with the normal operation of electronic circuits?
A) Signal
B) Carrier wave
C) Noise
D) Modulation
17. What is the primary function of a CPU (Central Processing Unit) in a computer system?
A) To store data permanently
B) To display output
C) To execute instructions and process data
D) To connect to the network
18. Which semiconductor device is commonly used in power supplies for voltage regulation?
A) Light Emitting Diode (LED)
B) Zener Diode
C) Photodiode
D) Varactor Diode
19. What is the fundamental difference between a P-type and an N-type semiconductor?
A) P-type has excess electrons, N-type has excess holes
B) P-type has excess holes, N-type has excess electrons
C) P-type conducts electricity, N-type does not
D) N-type conducts electricity, P-type does not
20. What does 'RF' stand for in electronics?
A) Resonant Frequency
B) Radio Frequency
C) Rectified Frequency
D) Reduced Frequency
21. Which type of electronic component is used to store data in most modern computers?
A) Vacuum Tube
B) Resistor
C) Integrated Circuit (IC)
D) Capacitor
22. What is the function of a 'modem'?
A) To amplify signals
B) To convert digital signals to analog and vice versa
C) To rectify AC to DC
D) To generate radio waves
23. In fiber optic communication, what phenomenon is used to guide light signals?
A) Diffraction
B) Interference
C) Total Internal Reflection
D) Polarization
24. What is the main characteristic of a superconductor at or below its critical temperature?
A) Increased resistance
B) Zero electrical resistance
C) Paramagnetism
D) Ferromagnetism
25. Which of the following is a basic building block of digital electronic circuits?
A) Operational Amplifier (Op-amp)
B) Inductor
C) Logic Gate
D) Potentiometer
26. What is the term for the phenomenon where a signal's amplitude decreases as it travels through a medium?
A) Amplification
B) Attenuation
C) Reflection
D) Refraction
27. Which type of semiconductor doping creates an excess of free electrons?
A) P-type doping
B) N-type doping
C) Intrinsic doping
D) Extrinsic doping
28. What is the primary function of a filter circuit?
A) To amplify signals
B) To block or pass signals of specific frequencies
C) To rectify AC to DC
D) To store energy
29. Which logic gate outputs '1' only if all inputs are '0'?
A) AND gate
B) OR gate
C) NAND gate
D) NOR gate
30. What is the term for the process of converting an analog signal into a digital signal?
A) Analog-to-Digital Conversion (ADC)
B) Digital-to-Analog Conversion (DAC)
C) Modulation
D) Demodulation
31. What is the term for the process of converting a digital signal into an analog signal?
A) Analog-to-Digital Conversion (ADC)
B) Digital-to-Analog Conversion (DAC)
C) Modulation
D) Demodulation
32. Which communication technique involves dividing a single communication channel into multiple time slots?
A) Frequency Division Multiplexing (FDM)
B) Code Division Multiplexing (CDM)
C) Time Division Multiplexing (TDM)
D) Wavelength Division Multiplexing (WDM)
33. What is the function of an oscillator circuit?
A) To convert AC to DC
B) To amplify a signal
C) To generate a repetitive waveform (signal)
D) To store digital data
34. What is the 'band gap' in a semiconductor material?
A) The energy required to ionize an atom
B) The energy range where electrons can move freely
C) The energy difference between the valence band and the conduction band
D) The energy level of the Fermi level
35. Which type of transistor uses a gate, drain, and source terminal?
A) Bipolar Junction Transistor (BJT)
B) Field-Effect Transistor (FET)
C) Unijunction Transistor (UJT)
D) Insulated Gate Bipolar Transistor (IGBT)
36. What is the primary advantage of digital communication over analog communication?
A) Higher bandwidth requirement
B) Greater susceptibility to noise
C) Improved accuracy and noise immunity
D) Simpler signal processing
37. An inductor stores energy in what type of field?
A) Electric field
B) Magnetic field
C) Gravitational field
D) Thermal field
38. What is the unit of electrical inductance?
A) Farad
B) Ohm
C) Henry
D) Siemens
39. Which component opposes the flow of electric current and dissipates energy as heat?
A) Capacitor
B) Inductor
C) Resistor
D) Transistor
40. What does 'FM' stand for in radio communication?
A) Frequency Modulation
B) Fast Messaging
C) Field Modulation
D) Full Mode
41. What does 'AM' stand for in radio communication?
A) Audio Modulation
B) Amplitude Modulation
C) Analog Memory
D) Automatic Metering
42. What is the function of a rectifier circuit?
A) To convert AC to DC
B) To convert DC to AC
C) To amplify signals
D) To filter out noise
43. Which semiconductor device is primarily used for switching and amplification of electronic signals?
A) Diode
B) Resistor
C) Transistor
D) Inductor
44. What is the main purpose of a capacitor in a circuit?
A) To limit current flow
B) To store energy in an electric field
C) To increase voltage
D) To generate heat
45. What is the unit of electrical capacitance?
A) Ohm
B) Farad
C) Ampere
D) Volt
46. Which type of resistor's resistance changes significantly with temperature?
A) Potentiometer
B) Rheostat
C) Thermistor
D) Varistor
47. What does 'LED' stand for?
A) Light Emitting Device
B) Light Electron Diode
C) Light Emitting Diode
D) Low Energy Detector
48. A transistor typically has how many terminals?
A) Two
B) Three
C) Four
D) One
49. What is the primary function of a diode in an electronic circuit?
A) To amplify a signal
B) To store electrical charge
C) To allow current flow in one direction only
D) To oscillate at a specific frequency
50. Which fundamental semiconductor material is most commonly used in integrated circuits (ICs)?
A) Gallium Arsenide (GaAs)
B) Silicon (Si)
C) Germanium (Ge)
D) Indium Phosphide (InP)
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