# Class 12 Physics MCQ – Basic Terminology Used in Electronic Communication Systems

This set of Class 12 Physics Chapter 15 Multiple Choice Questions & Answers (MCQs) focuses on “Basic Terminology Used in Electronic Communication Systems”.

1. What is the electrical analogue of the information produced by the source?
a) Attenuation
b) Amplification
c) Signal
d) Modulation

Explanation: Signal is the electrical analogue of the information produced by the source. It may be defined as a single-valued function of time (that conveys the information) and which, at every instant of time, takes a unique value.

2. What is defined as the largest distance between the source and the destination upto which a signal can be received with sufficient strength?
a) Modem
b) Range
c) Attenuation
d) Amplification

Explanation: Range is defined as the largest distance between the source and the destination upto which a signal can be received with sufficient strength. Generally, it is the difference between the highest and the lowest values.

3. Identify the device which is a combination of a transmitter, an amplifier and a receiver which picks up a signal and retransmits it.
a) Multi-tandem transmitter
b) Repeater
c) Amplifier
d) Modem

Explanation: A repeater is a combination of a transmitter, an amplifier and a receiver which picks up a signal from the transmitter, amplifies and retransmits it to the receiver sometimes with a change of carrier frequency.

4. What refers to the band of frequencies of the original signal?
a) Range
c) Bandwidth
d) Baseband

Explanation: The term baseband refers to the band of frequencies of the original signal, i.e. a signal that is not changed by the modulation, as is produced by the source of information. For example, an audio signal may have a baseband range from 20 to 20,000 hertz.

5. ‘X’ refers to the frequency range over which equipment operates or the range over which the frequencies in a signal vary. Identify ‘X’.
a) Range
b) Repeater
c) Bandwidth
d) Baseband

Explanation: Bandwidth refers to the frequency range over which equipment operates or the range over which the frequencies in a signal vary. It is the particular range of frequencies for transmitting a signal. Therefore, X is bandwidth.
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6. A transmitter is a device which recovers the original message signal from the signal received at the output of the communication channel.
a) True
b) False

Explanation: No, this statement is false. The receiver is a device which recovers the original message signal from the signal received at the output of the communication channel. Whereas, a transmitter transmits it to the receiving end through a transmission medium.

7. What is the loss of strength of a signal during its propagation called?
a) Attenuation
b) Amplification
c) Bandwidth
d) Noise

Explanation: The loss of strength of a signal when travelling through the transmission medium is called attenuation. This makes the signal to become distorted. Attenuation also refers to the reduction in the amplitude of a signal.

8. What is meant by the term communication?
a) Transfer of information
b) Transfer of bytes
c) Transfer of knowledge
d) Transfer of funds

Explanation: The word communication refers to the faithful transfer of information or message from one point to another point in an intelligible form. The information is first converted into electrical signals and then sent electronically.

9. Name the device which converts energy from one form to another.
a) Transformer
b) Modem
c) Transducer
d) Repeater

Explanation: Any device that converts energy from one form to another is called a transducer. Transducers convert the corresponding variations in the electrical signal at its output.

10. Name the process of recovering the original information signal from the modulated wave at the receiver end.
a) Attenuation
b) Demodulation
c) Modulation
d) Bandwidth

Explanation: The process of recovering the original information signal from the modulated wave at the receiver end is called demodulation or detection. It is the reverse process of the modulation process that occurs at the transmitting end.

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