Radio

Why do radios have antennas?

• To convert radio waves into sound

• To pick up radio waves from the air

• To convert high-frequency signals into low-frequency signals

• To prevent unauthorized broadcasts from being picked up

Different radio stations broadcast their signals at different:

• Frequencies

• Altitudes

• Speeds

• Volumes

Place the following events in sequence:

• A receiver picks up a signal

• A transmitter modulates a carrier wave

• An antenna broadcasts radio waves

What might happen if a receiver didn't amplify radio waves?

• The waves wouldn't be able to travel very far

• Radio signals could not be separated from carrier waves

• The receiver wouldn't be able to pick up radio waves

• You wouldn't be able to hear anything through your radio

What is the central difference between AM and FM signals?

• FM signals have much higher frequencies

• FM signals have much longer wavelengths

• AM signals can only travel short distances

• AM signals can only broadcast speech, not music

What phenomenon allows radio waves to be transmitted over very long distances?

• Translation

• Refraction

• Reflection

• Diffraction

If you live in Chicago, and are listening to a radio broadcast from London, your receiver is picking up:

• Short waves

• Low-amplitude waves

• AM waves

• FM waves

How do very high frequency waves differ from other forms of radio waves?

• They bounce off the ionosphere

• They pass through the ionosphere

• They are absorbed by the ionosphere

• They are diffused by the ionosphere

If you tune your radio to 92.3 on the FM dial, what waves are you picking up?

• High-amplitude waves with a frequency of 92.3 waves per second

• Low-frequency waves with a wavelength of 92.3 centimeters

• Carrier waves with a frequency of 92.3 million waves per second

• Short waves with an amplitude of 92.3 millimeters

What do radio waves have in common with other electromagnetic waves?

• They have the same frequency

• They have the same amplitude

• They have the same wavelength

• They have the same speed