Electromagnetic Waves and the Electromagnetic Spectrum

A set of flashcards covering key concepts about electromagnetic waves and the electromagnetic spectrum.

How are electromagnetic waves made

vibrating electric charges.

How do electric and magnetic fields operate in relation to electromagnetic waves?

They operate even in empty space, and changing magnetic fields create changing electric fields and vice versa.

What happens to frequency and wavelength in electromagnetic waves?

Frequency and wavelength are inversely proportional; as frequency increases, wavelength decreases.

What unit is frequency measured in?

Frequency is measured in hertz.

How is wavelength defined?

Wavelength is the distance from one crest to another, measured in meters.

What is the speed of electromagnetic waves in a vacuum?

The speed of electromagnetic waves in a vacuum is 300,000 m/s.

How do electromagnetic waves behave in matter compared to a vacuum?

Electromagnetic waves slow down as they travel through matter.

What does the electromagnetic spectrum represent?

The electromagnetic spectrum is the entire range of electromagnetic wave frequencies.

What are radio waves?

Radio waves are low-frequency electromagnetic waves with wavelengths from less than a centimeter to about 1,000 meters.

What is the purpose of radar?

Radar uses radio waves bounced off of an object to determine its speed and location.

What do microwaves refer to in terms of radio wavelengths?

Microwaves refer to radio wavelengths of about 1 to 10 centimeters.

What are infrared waves?

Infrared waves are electromagnetic waves with a slightly higher frequency than radio waves; they are felt as warmth.

What is the wavelength range of visible light?

Visible light has wavelengths between about 390-770 billionths of a meter.

What are the characteristics of ultraviolet waves?

Ultraviolet waves have frequencies slightly higher than visible light and can damage skin; they can also kill bacteria.

What role does the ozone layer play in relation to ultraviolet light?

The ozone layer above Earth's surface absorbs most of the sun's harmful ultraviolet rays.

What are X-rays and gamma rays used for?

X-rays are used to provide images of bones and for security checks, while gamma rays are ultra-high-frequency electromagnetic waves that can damage cells.

What is radiation therapy?

Radiation therapy is used to kill damaged cells.