Electromagnetic Spectrum, Doppler Effect, and Telescopes Test Review

Practice vocabulary flashcards covering the electromagnetic spectrum, wave properties, Doppler effect, and telescopes from the test review sheet.

Electromagnetic spectrum

The entire range of electromagnetic waves from low frequency to high frequency.

Electromagnetic energy

The specific type of energy that is transferred by electromagnetic waves.

Speed of light

The speed at which all electromagnetic waves travel through empty space.

Medium

A substance such as a solid, liquid, or gas, which electromagnetic waves do not require to travel through.

Frequency

The number of waves that pass a certain point each second.

Radio waves

Electromagnetic waves with the lowest frequency and longest wavelength, possessing longer wavelengths and lower frequencies than infrared waves.

Sound waves

A type of wave that requires a medium and is not an electromagnetic wave.

X-Ray

An electromagnetic wave with a very short wavelength that is able to pass through many different materials and is used in medical imaging.

Visible light

The part of the electromagnetic spectrum that the human eye is able to see.

Ultraviolet (UV) waves

Electromagnetic waves that form part of the energy that comes from the Sun.

Microwave

A form of radio wave with a shorter wavelength and higher frequency than standard radio waves.

Gamma ray

The most energetic form of electromagnetic radiation, having the highest frequency and shortest wavelength of all electromagnetic waves.

Infrared wave

An electromagnetic wave with a shorter wavelength and higher frequency than a microwave, commonly used in remote controls.

Electromagnetic spectrum order (by frequency)

The sequence of electromagnetic waves arranged from lowest to highest frequency: Radio, Microwave, Infrared, Visible Light, Ultraviolet, X-Ray, and Gamma.

Hydrogen absorption spectrum

A series of spectral absorption lines used as a standard to compare against star spectra to detect motion toward or away from Earth.

Doppler Effect

An alteration in wave frequency or wavelength due to relative motion between the source and the observer.

Red shift

A shift in spectral lines toward longer wavelengths that occurs when a star or celestial body moves away from Earth.

Blue shift

A shift in the spectral lines of a distant galaxy or star indicating that it is moving closer to Earth.

Approaching motion (Doppler Effect)

The scenario where a source and observer move towards each other, causing the observed wave frequency to increase.

Receding motion (Doppler Effect)

The scenario where an object moves away from an observer, causing the observed wave frequency to decrease.

Telescope

A device astronomers use to see faraway objects.

Mirrors or lenses

The optical components used by most large telescopes to gather and focus light.

Galileo Galilei

The scientist who made the telescope famous by observing sunspots, Saturn's rings, and Jupiter's moons.

Optical telescope

A type of telescope designed to detect visible light.

Refracting telescope

A telescope that uses lenses to bend light toward a focal point.

Reflecting telescope

A telescope that uses a curved mirror to redirect light to a focal point.

Curved mirror

The reflective optical component used in a reflecting telescope to redirect light to a focal point.

Lenses (in telescopes)

Transparent optical elements used in refracting telescopes to bend incoming light toward a focal point.

Focus (focal point)

The point where light rays come together.

Radio telescope

A type of telescope used to detect radio waves coming from space.

Hubble Space Telescope

A space telescope that produces clearer images than ground telescopes because it is located above Earth's atmosphere.

Atmospheric turbulence

The primary cause of the twinkling of stars as seen from ground-based observation.

Light-gathering power

A telescope property that depends mainly on the size (diameter) of the mirror or lens.

Vacuum propagation (Electromagnetic waves)

The characteristic ability of electromagnetic waves to travel through empty space without requiring a material medium.

Spectral lines

Discrete lines formed in an absorption or emission spectrum that shift toward red or blue depending on an object's relative motion.