1.
Communication is the process of:
Correct Answer
C. Exchanging information
Explanation
Communication is the process of exchanging information between individuals or groups. It involves the transmission and reception of messages, ideas, or thoughts through various channels, such as verbal, nonverbal, written, or visual. Through communication, people can share knowledge, express emotions, convey instructions, and establish connections with others. It plays a crucial role in facilitating understanding, collaboration, and building relationships in personal, social, and professional settings.
2.
Two key barriers to human communications are:
Correct Answer
A. Distance and Language
Explanation
Distance and language are two key barriers to human communication. Distance refers to the physical separation between individuals, which can make it difficult to convey messages effectively. Language, on the other hand, refers to the different languages spoken by individuals, which can lead to misunderstandings and misinterpretations. These barriers hinder effective communication and require individuals to find ways to overcome them, such as using translators or technology to bridge the gap. Ignorance and noise can also be barriers to communication, but they are not specifically mentioned in the question.
3.
Electronic communications were discovered in which century?
Correct Answer
C. Nineteenth
Explanation
Electronic communications were discovered in the nineteenth century. This was a time of significant advancements in technology, including the development of telegraphy and the invention of the telephone. These innovations revolutionized communication by allowing messages to be sent and received over long distances, marking the beginning of electronic communications as we know them today.
4.
Which of the following is not a major communications medium?
Correct Answer
B. Water
Explanation
Water is not a major communications medium because it does not have the ability to transmit information or signals in the same way as free space, wires, or fiber optic cables. While water may be used for underwater communication in certain scenarios, it is not widely used or considered a primary medium for communication.
5.
Random interference to transmitted signals is called:
Correct Answer
D. Noise
Explanation
Noise refers to random interference that affects transmitted signals. It can disrupt the clarity and quality of the signal, making it difficult to interpret or understand. This interference can be caused by various factors, such as electromagnetic interference, atmospheric conditions, or electrical equipment. Noise can introduce errors or distortions in the signal, making it important to minimize its impact for effective communication.
6.
The communications medium causes the signal to be:
Correct Answer
C. Attenuated
Explanation
Attenuation refers to the decrease in the strength or intensity of a signal as it travels through a communication medium. This can occur due to factors such as distance, obstacles, or interference. In this case, the correct answer suggests that the communications medium causes the signal to be weakened or attenuated. Amplification would increase the signal strength, modulation would change the characteristics of the signal, and interference would disrupt or distort the signal.
7.
Which of the following is not a source of the noise?
Correct Answer
A. Another communications signal
Explanation
Another communications signal can indeed be a source of noise in a communication system. When multiple signals are present in the same frequency range, they can interfere with each other and result in noise. This interference is commonly known as cross-talk. Therefore, the given answer is incorrect as another communications signal can contribute to the noise in a system.
8.
One-way communications are called:
Correct Answer
D. Simplex
Explanation
One-way communications refer to a communication system where information flows in only one direction. In simplex communication, data can only be transmitted from one point to another, but not in the opposite direction. This means that the communication is unidirectional, with no feedback or response from the receiving end. Therefore, simplex is the correct term to describe one-way communications.
9.
Simultaneous two-way communications are called:
Correct Answer
B. Full duplex
Explanation
Simultaneous two-way communications, where both parties can transmit and receive data at the same time, are referred to as full duplex. In full duplex mode, there is no need to alternate between sending and receiving, as both operations can occur simultaneously. This allows for faster and more efficient communication compared to half duplex, where data can only be transmitted in one direction at a time. Bicomm and simplex do not accurately describe simultaneous two-way communications.
10.
The original electrical information signal to be transmitted is called:
Correct Answer
C. Baseband signal
Explanation
The original electrical information signal that is to be transmitted is referred to as the baseband signal. This signal is typically a low-frequency signal that carries the actual information to be transmitted. It is called the baseband signal because it is the original signal before any modulation or frequency conversion takes place. The baseband signal is then modulated onto a carrier signal to enable efficient transmission over a communication channel.
11.
The process of modifying a high-frequency carrier with the information to be transmitted is called:
Correct Answer
D. Modulation
Explanation
Modulation is the process of modifying a high-frequency carrier with the information to be transmitted. This is done by varying one or more of the carrier's properties, such as amplitude, frequency, or phase, in accordance with the signal to be transmitted. Modulation allows the information to be efficiently transmitted over long distances and received accurately at the destination. Multiplexing involves combining multiple signals into a single transmission, telemetry refers to the remote measurement and transmission of data, and detection is the process of extracting the original signal from a modulated carrier.
12.
The process of transmitting two or more information signals simultaneously over the same channel is called:
Correct Answer
A. Multiplexing
Explanation
Multiplexing is the correct answer because it refers to the process of transmitting multiple information signals simultaneously over the same channel. This technique allows for efficient use of the channel's capacity by dividing it into multiple smaller channels, each carrying a different signal. Multiplexing is commonly used in telecommunications and networking systems to transmit voice, data, and video signals concurrently.
13.
Continuous voice or video signals are referred to as being:
Correct Answer
B. Analog
Explanation
Analog signals refer to continuous voice or video signals that are represented by a continuous range of values. These signals are not discrete or quantized, but rather vary smoothly over time. They can take on any value within their range and are commonly used in audio and video transmission. Baseband refers to the original frequency range of a signal, while digital signals are discrete and represented by a series of binary values. Continuous wave refers to a single frequency wave that does not carry any information.
14.
Recovering information from a carrier is known as:
Correct Answer
C. Detection
Explanation
Detection is the correct answer because it refers to the process of extracting the original information from a modulated carrier signal. In communication systems, modulation is used to encode the information onto a carrier wave, and detection is then performed at the receiver to recover the original information. This involves demodulating the carrier signal and extracting the encoded information. Therefore, detection accurately describes the process of recovering information from a carrier.
15.
Transmission of graphical information over the telephone network is accomplished by:
Correct Answer
D. Facsimile
Explanation
Facsimile, also known as fax, is the correct answer because it is a technology that allows the transmission of graphical information over the telephone network. Facsimile machines scan documents and convert them into electronic signals that can be sent over telephone lines to a receiving fax machine, which then prints out a copy of the original document. This technology has been widely used for transmitting documents, images, and other graphical information quickly and efficiently over long distances.
16.
Measuring physical conditions at some remote location and transmitting this data for analysis is the process of:
Correct Answer
A. Telemetry
Explanation
Telemetry is the process of measuring physical conditions at a remote location and transmitting this data for analysis. It involves the use of sensors or instruments to gather data, which is then transmitted through a communication system to a central location for analysis and monitoring. Telemetry is commonly used in various fields such as remote monitoring of environmental conditions, space exploration, and healthcare. It allows for real-time data collection and analysis, enabling remote monitoring and control of systems and processes.
17.
Receiving electromagnetic emissions from stars is called:
Correct Answer
C. Radio astronomy
Explanation
Radio astronomy is the correct answer because it refers to the study of celestial objects by detecting and analyzing their radio waves. This involves receiving electromagnetic emissions from stars and other celestial bodies using radio telescopes. Unlike optical astronomy, which relies on visible light, radio astronomy allows scientists to observe objects that may not emit visible light but emit radio waves. Astrology is not the correct answer as it is a pseudoscience that claims to interpret the influence of celestial bodies on human affairs. Space surveillance is also not the correct answer as it refers to the monitoring and tracking of man-made objects in space.
18.
A personal communications hobby for individuals is:
Correct Answer
A. Ham radio
Explanation
Ham radio refers to the amateur radio service that allows individuals to communicate with others using radio frequencies. It is considered a personal communications hobby because it is a recreational activity pursued by individuals who have an interest in radio technology and communication. Ham radio operators can communicate with people from around the world, participate in contests, and provide emergency communication services during disasters. It requires a license and offers a wide range of communication options, making it a popular choice for hobbyists interested in radio communication.
19.
Radar is based upon:
Correct Answer
D. Reflected radio signals
Explanation
Radar operates by sending out radio signals and then detecting the reflected signals that bounce back from objects in its path. This allows radar to determine the distance, speed, and location of these objects. Therefore, the correct answer is "Reflected radio signals."
20.
A frequency of 27 MHz has a wavelength of approximately:
Correct Answer
A. 11m
Explanation
The wavelength of a wave can be calculated using the formula: wavelength = speed of light / frequency. In this case, the frequency is given as 27 MHz. Since the speed of light is approximately 3 x 10^8 meters per second, we can calculate the wavelength as follows: wavelength = (3 x 10^8 m/s) / (27 x 10^6 Hz) = 11.11 meters. Therefore, the wavelength of a frequency of 27 MHz is approximately 11 meters.
21.
Radio signals are made up of:
Correct Answer
B. Electric and magnetic fields
Explanation
Radio signals are made up of electric and magnetic fields. These fields are generated by the movement of electrons in an antenna. As the electrons oscillate back and forth, they create changes in the electric and magnetic fields, which then propagate through space as radio waves. These waves can be detected by a receiver and converted back into electrical signals, allowing us to listen to radio broadcasts or communicate wirelessly.
22.
The voice frequency range is:
Correct Answer
B. 300 to 3000 Hz
Explanation
The voice frequency range refers to the range of frequencies that are typically produced by the human voice. This range allows for the production of various speech sounds and is important for clear communication. The correct answer, 300 to 3000 Hz, falls within the typical range for voice frequencies and encompasses the majority of the frequencies used in speech production. Frequencies below 300 Hz are generally associated with lower-pitched sounds, while frequencies above 3000 Hz are more related to higher-pitched sounds.
23.
Another name for signals in the HF range is:
Correct Answer
C. Short waves
Explanation
Short waves is another name for signals in the HF range. HF stands for high frequency, and short waves refer to the shorter wavelengths of these signals. In the electromagnetic spectrum, HF signals have frequencies ranging from 3 to 30 MHz. They are commonly used for long-distance communication, especially in radio broadcasting and amateur radio operations. The term "short waves" is often used interchangeably with HF waves to describe these signals.
24.
Television broadcasting occurs in what ranges?
Correct Answer
C. VHF
Explanation
Television broadcasting occurs in the VHF range. VHF stands for Very High Frequency and it refers to the range of electromagnetic waves with frequencies between 30 MHz and 300 MHz. This range is commonly used for television broadcasting as it allows for the transmission of signals over long distances with good signal quality. VHF signals can penetrate buildings and obstacles better than UHF signals, making it a preferred choice for broadcasting television programs.
25.
Electromagnetic waves produced primarily by heat is called:
Correct Answer
A. Infrared rays
Explanation
Infrared rays are electromagnetic waves that are primarily produced by heat. These waves have longer wavelengths than visible light and are often associated with thermal radiation. They are commonly used in applications such as remote controls, night vision devices, and thermal imaging cameras. Infrared rays are not produced by microwaves, shortwaves, or X-rays.
26.
A micron is:
Correct Answer
B. One-millionth of a meter
Explanation
A micron is a unit of length that is equal to one-millionth of a meter. It is commonly used to measure very small distances, such as the size of microorganisms or the thickness of a human hair.
27.
The frequency range of infrared rays is approximately:
Correct Answer
D. 0.7 to 100 um
Explanation
The correct answer is 0.7 to 100 um. Infrared rays have a wavelength range between 0.7 and 100 micrometers (um). This range falls within the electromagnetic spectrum between visible light and microwaves. Infrared radiation is commonly used in various applications, such as remote controls, thermal imaging, and communication systems.
28.
The approximate wavelength of red light is:
Correct Answer
B. 7000 A
Explanation
The approximate wavelength of red light is 7000 A. This is because red light has a longer wavelength compared to other visible colors, such as blue or green. The unit "A" stands for Angstrom, which is a unit of length equal to 0.1 nanometers. Therefore, 7000 A is equivalent to 700 nanometers, which falls within the range of wavelengths typically associated with red light.
29.
Which of the following is not used for communications?
Correct Answer
A. X-rays
Explanation
X-rays are not used for communications because they have a very high frequency and short wavelength, which makes them suitable for medical imaging and industrial applications, but not for transmitting signals over long distances. In contrast, millimeter waves, infrared, and microwaves are all used for various forms of communication, such as wireless internet, satellite communication, and remote control devices.
30.
A signal occupies the spectrum space from 1.115 to 1.122 GHz. The bandwidth is:
Correct Answer
B. 7 MHz
Explanation
The bandwidth of a signal is the range of frequencies it occupies. In this case, the signal occupies the spectrum space from 1.115 to 1.122 GHz. To find the bandwidth, we subtract the lower frequency from the higher frequency: 1.122 GHz - 1.115 GHz = 0.007 GHz. Since 1 GHz is equal to 1000 MHz, the bandwidth is 0.007 GHz * 1000 MHz/GHz = 7 MHz. Therefore, the correct answer is 7 MHz.
31.
In the United States, the electromagnetic spectrum is regulated and managed by:
Correct Answer
C. FCC
Explanation
The correct answer is FCC. The Federal Communications Commission (FCC) is responsible for regulating and managing the electromagnetic spectrum in the United States. They oversee various aspects of communication, including radio, television, wire, satellite, and cable. The FCC ensures that the spectrum is efficiently allocated and used, while also enforcing rules and regulations to promote fair competition and protect consumers.
32.
For a given bandwidth signal, more channel space is available for signals in the range of:
Correct Answer
D. EHF
Explanation
The correct answer is EHF. EHF stands for Extremely High Frequency, and signals in this frequency range have a higher bandwidth available compared to signals in VHF, UHF, and SHF ranges. This means that EHF signals can transmit more data or information simultaneously, making it suitable for applications that require high-speed and high-capacity communication, such as satellite communication and wireless internet.