Radio Waves and Applications

Which property best makes radio waves safe for diagnosing illnesses through magnetic resonance imaging? Which property best makes radio waves useful for space research?

1. Low energy of radio waves 2. long wavelengths of radio waves

Order the steps to describe how information is sent. A signal is produced. A signal is seen, heard, or used. Radio waves are modulated and amplified. Radio waves are amplified and demodulated.

A signal is produced. ( 1. ) A signal is seen, heard, or used. ( 4. ) Radio waves are modulated and amplified. ( 2. ) Radio waves are amplified and demodulated. ( 3. )

Which type of modulation is used in these technologies?

AM programs: ✔ amplitude modulation Cell phones: frequency modulation✔ FM programs: frequency modulation✔ Television: amplitude modulation and frequency modulation✔

How are amplitude modulation and frequency modulation techniques similar? Both are used by cell phones to produce images. Both transform electrical signals into sound waves. Both modify the pulse of a carrier wave. Both are used by radio stations to transmit sound.

Both are used by radio stations to transmit sound.

Lena would like to be able to know her exact location on a map as she travels across the country. Which technology would best help Lena? CB radio, because it uses HF radio waves MRI, because it uses magnets to produce a picture radio telescope, because it captures radio waves from space GPS, because it uses satellites that provide position and velocity data

GPS, because it uses satellites that provide position and velocity data

Jasmine broke the antenna on her radio receiver. How will this most likely affect Jasmine's radio? It will not change the amplitude of the carrier waves. It will not change the frequency of the carrier waves. It will not send out modulated radio waves. It will not capture modulated radio waves.

It will not capture modulated radio waves.

Explain why radio and television stations use different frequencies to broadcast programs.

Sample Response: Radio and television stations use different frequencies to broadcast programs to avoid interference. Interference may degrade the quality of signals.

Research is being done on the use of radio waves in destroying cancer cells. What type of frequency would be best used in this technology? Justify your answer.

Sample Response: The destruction of cancer cells requires a lot of energy, so high-frequency radio waves can be used in this technology because they have high energy.

Savanna drew a diagram to show how radio waves are modified for use in the field of broadcasting. Which best describes Savanna's error? The label at the top of the diagram should be "FM Radio," not "Cell Phone." The FM carrier waves should have different frequencies than the carrier waves, not different amplitudes. The carrier wave should be on the right of the modulator, not on the left of the modulator. The modulator should be labeled "Amplitude modulator," not "Frequency modulator."

The FM carrier waves should have different frequencies than the carrier waves, not different amplitudes.

Which best explains why an MRI is useful for diagnosing cancer but ineffective in treating it? The frequency of the radio waves used is so high that the waves cannot be used to target specific cells. The wavelength of the radio waves used is so short that the waves cannot be used to target specific cells. The amount of energy carried by radio waves is enough to provide images but not enough to kill cells. The amount of energy carried by radio waves is so high that it provides images but can also damage cells.

The amount of energy carried by radio waves is enough to provide images but not enough to kill cells.

Which statement correctly differentiates between transmitters and receivers? Transmitters have antennas, and receivers do not have antennas. Transmitters send radio waves, and receivers capture radio waves. Transmitters have demodulators, and receivers have modulators. Transmitters do not have amplifiers, and receivers have amplifiers.

Transmitters send radio waves, and receivers capture radio waves.

Huan made a chart to study for an exam about radio waves Which headings best complete the chart? X: PhaseY: Pulse X: PulseY: Phase X: AMY: FM X: FMY: AM

X: FM Y: AM

Paul made a diagram to compare and contrast radio waves that are used for communication and for broadcasting. Which labels belong in the areas marked X, Y, and Z? X: May use LF, HF, and UHF wavesY: Travels at the speed of lightZ: May use MF and VHF waves X: Travels at the speed of lightY: May use LF, HF, and UHF wavesZ: May use MF and VHF waves X: May use MF and VHF wavesY: May use LF, HF, and UHF wavesZ: Uses radio waves with long wavelengths X: Uses radio waves with long wavelengthsY: May use LF, HF, and UHF wavesZ: May use MF and HF waves

X: May use LF, HF, and UHF waves Y: Travels at the speed of light Z: May use MF and VHF waves

The primary job of a(n) ( ) is to increase the power of a modified radio wave.

amplifier

What kind of modulator is used in this scenario? ( ) modulator

amplitude

What type of modulation is typically used by broadcasting stations to transmit pictures on television screens? amplitude frequency phase pulse

amplitude

On a transmitter, a(n) ( )sends modulated carrier waves into the air.

antenna

The diagram shows a device that uses radio waves. What is the role of the part in the diagram labeled Y? modulate, amplify, and send out waves capture, amplify, and demodulate waves change the amplitude and frequency of waves change the pulse and phase of waves

capture, amplify, and demodulate waves

Which type of modulation is applied to radio-controlled toys? amplitude frequency phase pulse

pulse

In 2010, scientists obtained an image of an asteroid that was dangerously close to Earth. Which technology did the scientists likely use to capture the image? GPS, because it uses satellites that provide position and velocity data radio telescope, because it captures radio waves from space MRI, because it uses magnets to produce a picture submarine communication, because it uses LF radio waves

radio telescope, because it captures radio waves from space

Which technology uses low frequency (LF) radio waves? space communication FM radio broadcasting TV program broadcasting submarine communication

submarine communication

Which terms describe the purpose of antennas on devices that use radio waves? transmit and receive modify and amplify amplify and receive modify and transmit

transmit and receive