Waves Carry Information - Middle School Physical Science
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Which option is an example of information carried by light waves in a fiber-optic cable?
Which option is an example of information carried by light waves in a fiber-optic cable?
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Digital pulses of light representing $0$ and $1$. Light on/off patterns encode binary data through the fiber.
Digital pulses of light representing $0$ and $1$. Light on/off patterns encode binary data through the fiber.
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What does modulation mean in the context of transmitting information with waves?
What does modulation mean in the context of transmitting information with waves?
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Changing a carrier wave to encode a message. The carrier wave's properties are systematically varied to represent data.
Changing a carrier wave to encode a message. The carrier wave's properties are systematically varied to represent data.
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Which term names the wave that is modified to carry information over long distances?
Which term names the wave that is modified to carry information over long distances?
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Carrier wave. This base wave is modulated to carry the actual information signal.
Carrier wave. This base wave is modulated to carry the actual information signal.
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What is amplitude modulation (AM)?
What is amplitude modulation (AM)?
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Encoding by varying the wave amplitude. The wave's height changes to represent the information signal.
Encoding by varying the wave amplitude. The wave's height changes to represent the information signal.
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What is frequency modulation (FM)?
What is frequency modulation (FM)?
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Encoding by varying the wave frequency. The wave's cycles per second change to represent the signal.
Encoding by varying the wave frequency. The wave's cycles per second change to represent the signal.
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If a signal uses a higher frequency carrier, what happens to wavelength if speed stays constant?
If a signal uses a higher frequency carrier, what happens to wavelength if speed stays constant?
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Wavelength decreases. From $v = f\lambda$, if $v$ is constant and $f$ increases, $\lambda$ must decrease.
Wavelength decreases. From $v = f\lambda$, if $v$ is constant and $f$ increases, $\lambda$ must decrease.
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What is phase modulation in wave communication?
What is phase modulation in wave communication?
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Encoding by varying the wave phase. The wave's timing shifts relative to a reference to encode data.
Encoding by varying the wave phase. The wave's timing shifts relative to a reference to encode data.
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What is the key difference between analog and digital signals?
What is the key difference between analog and digital signals?
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Analog is continuous; digital uses discrete levels. Analog varies smoothly; digital jumps between set values.
Analog is continuous; digital uses discrete levels. Analog varies smoothly; digital jumps between set values.
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Which type of wave is commonly used for wireless communication through air or space?
Which type of wave is commonly used for wireless communication through air or space?
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Electromagnetic waves. EM waves travel through vacuum, ideal for long-distance transmission.
Electromagnetic waves. EM waves travel through vacuum, ideal for long-distance transmission.
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What is binary encoding in digital communication?
What is binary encoding in digital communication?
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Representing information using $0$ and $1$. Two states (on/off) represent all information digitally.
Representing information using $0$ and $1$. Two states (on/off) represent all information digitally.
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Which device converts information into a signal suitable for transmission?
Which device converts information into a signal suitable for transmission?
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Transmitter (encoder). It modulates a carrier wave with the information to be sent.
Transmitter (encoder). It modulates a carrier wave with the information to be sent.
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Which device extracts the message from a received wave signal?
Which device extracts the message from a received wave signal?
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Receiver (decoder/demodulator). It demodulates the carrier wave to recover the original information.
Receiver (decoder/demodulator). It demodulates the carrier wave to recover the original information.
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What is the definition of a signal in wave-based communication?
What is the definition of a signal in wave-based communication?
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A pattern of wave changes that carries information. Information is encoded in systematic variations of wave properties.
A pattern of wave changes that carries information. Information is encoded in systematic variations of wave properties.
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What is the function of an antenna in wave communication?
What is the function of an antenna in wave communication?
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It converts electrical signals to EM waves and back. Antennas radiate and capture electromagnetic waves efficiently.
It converts electrical signals to EM waves and back. Antennas radiate and capture electromagnetic waves efficiently.
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What is attenuation in a transmitted wave signal?
What is attenuation in a transmitted wave signal?
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Loss of signal strength (amplitude) with distance. Energy spreads out and is absorbed as waves travel.
Loss of signal strength (amplitude) with distance. Energy spreads out and is absorbed as waves travel.
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Which type of wave requires a material medium and can transmit information as sound?
Which type of wave requires a material medium and can transmit information as sound?
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Mechanical waves. Sound waves need matter to propagate, unlike EM waves.
Mechanical waves. Sound waves need matter to propagate, unlike EM waves.
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What is noise in the context of wave communication?
What is noise in the context of wave communication?
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Unwanted disturbances that alter the signal. Random interference corrupts the intended signal pattern.
Unwanted disturbances that alter the signal. Random interference corrupts the intended signal pattern.
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Which option best describes why FM is often clearer than AM in the presence of noise?
Which option best describes why FM is often clearer than AM in the presence of noise?
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Amplitude noise affects AM more than FM. FM encodes in frequency, unaffected by amplitude changes from noise.
Amplitude noise affects AM more than FM. FM encodes in frequency, unaffected by amplitude changes from noise.
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Identify the correct relationship for wave speed used in communication systems.
Identify the correct relationship for wave speed used in communication systems.
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$v = f\lambda$. Speed equals frequency times wavelength for all waves.
$v = f\lambda$. Speed equals frequency times wavelength for all waves.
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Which option correctly matches a communication method to its wave type: radio broadcast, phone call, sonar?
Which option correctly matches a communication method to its wave type: radio broadcast, phone call, sonar?
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Radio broadcast: EM; phone call: EM; sonar: mechanical (sound). Radio and phones use EM waves; sonar uses mechanical sound waves.
Radio broadcast: EM; phone call: EM; sonar: mechanical (sound). Radio and phones use EM waves; sonar uses mechanical sound waves.
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What is the equation relating wave speed, frequency, and wavelength for a signal wave?
What is the equation relating wave speed, frequency, and wavelength for a signal wave?
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$v = f\lambda$. Wave speed equals frequency times wavelength for all waves.
$v = f\lambda$. Wave speed equals frequency times wavelength for all waves.
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Identify the property that can encode information in a digital signal sent by waves.
Identify the property that can encode information in a digital signal sent by waves.
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Discrete changes in amplitude, frequency, or phase (bits $0$ and $1$). Digital signals use distinct states to represent binary data.
Discrete changes in amplitude, frequency, or phase (bits $0$ and $1$). Digital signals use distinct states to represent binary data.
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What is radar, and what type of wave does it use to carry information?
What is radar, and what type of wave does it use to carry information?
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Object detection using reflected radio (electromagnetic) waves. Radio waves reflect off objects to determine position and speed.
Object detection using reflected radio (electromagnetic) waves. Radio waves reflect off objects to determine position and speed.
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What is sonar, and what type of wave does it use to carry information?
What is sonar, and what type of wave does it use to carry information?
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Object detection using reflected sound waves. Sound waves bounce off objects to reveal their location underwater.
Object detection using reflected sound waves. Sound waves bounce off objects to reveal their location underwater.
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What is reflection used for in some wave-based technologies that transmit information?
What is reflection used for in some wave-based technologies that transmit information?
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To detect objects or distances by analyzing reflected waves. Echo timing reveals object location and distance information.
To detect objects or distances by analyzing reflected waves. Echo timing reveals object location and distance information.
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