Unit 2

Question 1

absorption spectrum

Answer 1

spectrum showing dark lines at some narrow color regions (wavelengths). The lines are formed by atoms absorbing light, which lifts their electrons to higher orbits

Question 2

blue shift

Answer 2

displacement of the spectrum to shorter wavelengths in the light coming from distant celestial objects moving toward the observer

Question 3

compound telescope

Answer 3

use a combination of lenses and mirrors

Question 4

continuous spectrum

Answer 4

Visible light can be separated into its parts by using a prism. The image you see here is a continuous spectrum of all visible light. This can also be done for other frequencies of EMR

Question 5

Doppler shift

Answer 5

observed change in the frequency of a wave when the source or observer is moving

Question 6

electromagnetic spectrum

Answer 6

range of wavelengths or frequencies over which electromagnetic radiation extends

Question 7

frequency

Answer 7

number of complete wavelengths that pass a point in a given time

Question 8

gamma rays

Answer 8

high energy, high frequency photon of electromagnetic radiation

Question 9

infrared radiation

Answer 9

electromagnetic radiation at wavelengths longer than the red end of visible light and shorter than microwaves (roughly between 1 and 100 microns). Almost none of the infrared portion of the electromagnetic spectrum can reach the surface of the Earth, although some portions can be observed by high-altitude aircraft (such as the Kuiper Observatory) or telescopes on high mountaintops (such as the peak of Mauna Kea in Hawaii).

Question 10

microwaves

Answer 10

electromagnetic radiation which has a longer wavelength (between 1 mm and 30 cm) than visible light. Microwaves can be used to study the Universe, communicate with satellites in Earth orbit, and cook popcorn

Question 11

photon

Answer 11

particle of electromagnetic radiation

Question 12

radiation

Answer 12

energy emitted in the form of waves (light) or particles (photons)

Question 13

radio telescope

Answer 13

gather radio emissions from stars, galaxies, and quasars through the use of a radio antenna and a radiometer

Question 14

radio waves

Answer 14

electromagnetic radiation which has the lowest frequency, the longest wavelength, and is produced by charged particles moving back and forth; the atmosphere of the Earth is transparent to radio waves with wavelengths from a few millimeters to about twenty meters

Question 15

red shift

Answer 15

change in the wavelength of light due to an object moving away from the observer

Question 16

reflecting telescope

Answer 16

have two mirrors–one to gather light and reflect it to the second mirror

Question 17

refracting telescope

Answer 17

basic telescope with two lenses: one larger objective lens and a smaller lens

Question 18

spectral lines

Answer 18

Astronomers use spectral lines to learn the following about objects in space: temperature, density, magnetic field, speed of movement, and elements present

Question 19

spectroscope

Answer 19

device that separates EMR into its component parts

Question 20

spectroscopy

Answer 20

an object’s light broken down into its different colors

Question 21

telescope

Answer 21

device used to enlarge images of distant objects

Question 22

ultraviolet

Answer 22

electromagnetic radiation at wavelengths shorter than the violet end of visible light; the atmosphere of the Earth effectively blocks the transmission of most ultraviolet light

Question 23

visible light

Answer 23

electromagnetic radiation at wavelengths which the human eye can see. We perceive this radiation as colors ranging from red (longer wavelengths; ~ 700 nanometers) to violet (shorter wavelengths; ~400 nanometers.)

Question 24

wavelength

Answer 24

distance from one point on a wave to the same point on an adjacent wave

Question 25

X-rays

Answer 25

electromagnetic radiation of very short wavelength and very high-energy; X-rays have shorter wavelengths than ultraviolet light but longer wavelengths than gamma rays