Deck 2: Light and Telescopes

Question 1

X-rays travel at a greater speed than radio waves.

Answer 1

False

Question 2

Gamma Rays are a type of electromagnetic radiation.

Answer 2

True

Question 3

As a star's temperature increases, the frequency of peak emission also increases.

Answer 3

True

Question 4

Molecular spectra, like elemental ones, involve only the vibration of the particles.

Question 5

All radio telescopes are reflectors in design.

Question 6

The shorter a wave's wavelength, the greater its energy.

Question 7

In blackbody radiation, the energy is radiated uniformly in every region of the spectrum, so the radiating body appears black in color.

Question 8

A blue star has a higher surface temperature than a red star.

Question 9

The absorption lines for a cool thin gas are identical in color and energy to the emission lines of the same gas if hot enough to glow.

Question 10

An X-ray photon has more energy than a visible photon.

Question 11

Wave energy can only be transmitted through a material medium.

Question 12

You would perceive a change in a visible light wave's amplitude as a change in its color.

Question 13

The primary purpose of an astronomical telescope is to magnify the images of distant objects, making them appear closer.

Question 14

In an atom, electrons can have only specific, allowed orbital energies.

Question 15

Observations in the X-ray portion of the spectrum are routinely done from the surface of the Earth.

Question 16

As white light passes through a prism, the red (longer) wavelengths bend less than the blue (shorter) wavelengths, so forming the rainbow of colors.

Question 17

The spectral lines of each element are distinctive to that element, whether we are looking at emission or absorption lines.

Question 18

The light gathering ability of a telescope is most dependent on the diameter of its primary objective.

Question 19

The red hydrogen alpha line carries more energy per photon than the blue-green hydrogen beta line does.

Question 20

An observer will measure the wavelength of waves emanating from a source that is moving away as longer than it really is.

Question 21

The hottest objects with temperatures in the millions of Kelvins, give off most of their radiation in which part of the electromagnetic spectrum?

A) Visible
B) Radio
C) Ultraviolet
D) X-ray
E) Gamma ray

Question 22

The temperature scale that places zero at the point where all atomic and molecular motion ceases is

A) Fahrenheit.
B) Celsius.
C) Kelvin.
D) centigrade.
E) Ransom.

Question 23

In addition to visible light, Hubble can do some work in the infrared and ultraviolet portions of the spectrum.

Question 24

Which type of radiation can be observed well from Earth's surface?

A) Gamma ray
B) X-ray
C) Ultraviolet
D) Visible
E) Infrared

Question 25

Stars like our Sun emit most of their light in which part of the electromagnetic spectrum?

A) The visible
B) The X-ray
C) The ultraviolet
D) The radio
E) The infrared

Question 26

Of all the forms of electromagnetic radiation, the one with the lowest frequency is

A) gamma rays.
B) ultraviolet rays.
C) visible light.
D) microwaves.
E) radio waves.

Question 27

The two forms of electromagnetic radiation that penetrate the atmosphere best are

A) X-rays and gamma rays.
B) ultraviolet and visible light.
C) visible and infrared light.
D) visible and radio waves.
E) infrared and microwaves.

Question 28

The wavelength at which a blackbody radiates most depends on its

A) radius.
B) mass.
C) magnetic fields.
D) temperature.
E) direction of motion.

Question 29

Which of these is constant for ALL types of electromagnetic radiation in a vacuum?

A) Amplitude
B) Wavelength
C) Frequency
D) Velocity
E) Photon energy

Question 30

The Doppler Effect is a phenomenon that allows one to measure an object's

A) temperature.
B) radius.
C) line-of-sight speed.
D) chemical composition.

Question 31

What is TRUE of a blackbody?

A) It appears black to us, regardless of its temperature.
B) Its energy is not a continuum.
C) Its energy peaks at the wavelength determined by its temperature.
D) If its temperature doubled, the peak in its curve would be doubled in wavelength.
E) It has a complete absence of thermal energy.

Question 32

The number of waves passing the observer per second is

A) the wavelength in angstroms.
B) the amplitude in nm.
C) the frequency in Hertz.
D) the period in seconds.
E) the energy in milliwatts.

Question 33

Due to our ozone layer, ultraviolet astronomy must be done from space.

Question 34

To see the Sun's hot corona (a temperature of 1,000,000 K), which part of the electromagnetic spectrum should one observe?

A) The visible
B) The X-ray
C) The ultraviolet
D) The radio
E) The infrared

Question 35

Consider this diagram. Which statement is TRUE?

A) The wavelength is 4.
B) The wavelength is 6.
C) The wavelength is 8.
D) The wavelength is 12.
E) The wavelength cannot be determined from this diagram.

Question 36

The visible color of electromagnetic radiation that has the shortest wavelength is

A) red.
B) orange.
C) green.
D) blue.
E) violet.

Question 37

The light from an object moving tangentially (to your left or right) will exhibit

A) a blueshift.
B) a redshift.
C) a shift in peak wavelength towards the red.
D) a shift in peak wavelength towards the blue.
E) no shift.

Question 38

If a wave's frequency doubles, its wavelength

A) is halved.
B) is also doubled.
C) is unchanged, as c is constant.
D) is now 4 times longer.
E) becomes 16 times longer.

Question 39

A wave's velocity is the product of the

A) frequency times the period of the wave.
B) period times the energy of the wave.
C) amplitude times the frequency of the wave.
D) frequency times the wavelength of the wave.
E) amplitude times the wavelength of the wave.

Question 40

Consider this diagram. Which statement is TRUE?

A) The amplitude is 4.
B) The amplitude is 6.
C) The amplitude is 8.
D) The amplitude is 12.
E) The amplitude cannot be determined from this diagram.

Question 41

An emission spectrum can be used to identify a(n)

A) proton.
B) electron.
C) neutron.
D) atom.
E) neutrino.

Question 42

The Orion Nebula, M-42, is a hot, thin cloud of glowing gas, so its spectrum is

A) a continuum, strongest in the color red.
B) a few bright lines against a dark background.
C) a few dark lines in the continuum.
D) a continuum, but with both bright and dark lines mixed in.
E) not in the visible portion of the spectrum.

Question 43

What are two advantages of large scopes over smaller ones?

A) Large scopes have a larger field of view and sharper focus.
B) Large scopes are not subject to atmospheric turbulence and opacity like smaller ones.
C) Large scopes are easier to mount and control than small ones.
D) Large telescope have more light gathering power and better resolution.
E) Large telescopes give higher magnification and are easier to build.

Question 44

What is the primary purpose of an astronomical telescope?

A) To magnify and make distant objects appear closer.
B) To separate light into its component colors.
C) To measure the intensity of light very accurately.
D) To access wavelengths that we cannot see visually.
E) To collect a lot of light and bring it to a focus.

Question 45

Radio dishes are large in order to

A) attract funding from NASA and the NSF.
B) give greater magnification.
C) increase their angular resolution and collect the very weak radio photons.
D) increase the range of waves they can collect.
E) detect shorter waves than optical telescopes for superior resolution.

Question 46

A hydrogen atom consists of an electron and a(n)

A) proton.
B) ion.
C) neutrino.
D) neutron.
E) lepton.

Question 47

Which of the following is a problem inherent in all large radio telescopes?

A) They are badly affected by poor seeing and atmospheric turbulence.
B) The lightest breeze shakes them, making the observations blurry.
C) Their waves are blocked by water vapor, so they must be located in deserts.
D) Radio waves have long wavelengths, so radio telescopes have poor resolution.
E) The dust clouds in the Milky Way block almost all wavelengths except light.

Question 48

This design combines the radiation from two different telescopes to greatly enhance resolution via computer synthesis.

A) Cassegrain reflector
B) Newtonian reflector
C) Prime focus reflector
D) Refractor
E) Interferometer

Question 49

A neon light (thin hot neon gas in a sealed tube) gives us

A) a continuous spectrum, since the neon is hot enough to glow.
B) a few bright emission lines, telling us the gas is neon.
C) a continuum, with dark lines identifying the neon atoms that are present.
D) a lot of random bright red lines due to the motion of the hot atoms.
E) nothing visible to us, but a lot of infrared lines as heat.

Question 50

In astronomy, an interferometer can be used to

A) yield better seeing conditions with optical telescopes.
B) decrease the effects of light pollution in getting darker sky backgrounds.
C) improve the angular resolution of radio telescopes.
D) increase the sensitivity of infrared telescopes to longer wavelengths.
E) speed up the processing of CCD images.

Question 51

The classical model of the hydrogen atom that explains its spectral line structure is due to

A) Kirchhoff.
B) Bohr.
C) Fraunhofer.
D) Newton.
E) Mendeleev.

Question 52

Why are molecular lines more complex than elemental spectral lines?

A) Molecules have two or more atoms.
B) Molecules can vibrate and rotate as well.
C) Molecules are heavier than atoms.
D) Molecules are the basis of life.
E) Most of the universe is made of molecules, not individual atoms.

Question 53

What is the resolution of a telescope?

A) Its ability to see very faint objects
B) Its ability to distinguish two adjacent objects close together in the sky
C) Its ability to make distant objects appear much closer to us
D) Its ability to separate light into its component colors for analysis
E) Its ability to focus more than just visible light for imaging

Question 54

In Bohr's model of the atom, electrons

A) only make transitions between orbitals of specific energies.
B) are not confined to specific orbits.
C) are spread uniformly through a large, positive mass.
D) can be halfway between orbits.
E) move from orbit to orbit in many small steps.

Question 55

Compared to optical telescopes, radio telescopes are built large because

A) they're less expensive to make than optical telescopes.
B) radio photons don't carry much energy.
C) atmospheric turbulence is more of a problem.
D) radio sources are harder to find.
E) radio waves are absorbed by the atmosphere.

Question 56

If a light source is approaching you at a speed very close to the speed of light, it will appear

A) redder than it is.
B) bluer than it is.
C) brighter than it is.
D) fainter than it is.
E) lower temperature than it is.

Question 57

What is TRUE of radio telescopes?

A) They have poorer angular resolution than a refractor.
B) They have better angular resolution than a reflector.
C) They are the smallest, most compact telescopes.
D) They can only be used above the atmosphere.
E) They are most sensitive to the opacity of the ozone layer.

Question 58

What is the light-gathering power of an 8-inch telescope compared to a 4-inch telescope?

A) 2× better
B) 4× better
C) 8× better
D) 16× better
E) 32× better

Question 59

What is spectroscopy?

A) An analysis of the way in which atoms absorb and emit light
B) A study of the geometry of rainbows
C) An observational technique to measure the brightness of light at different colors
D) The use of CCDs to capture light more efficiently than with photographic film
E) A method to freeze atmospheric turbulence for better resolution

Question 60

What problem does adaptive optics correct?

A) Defects in the optics of the telescope, such as the original Hubble mirror
B) The opacity of the Earth's atmosphere to some wavelengths of light
C) The light pollution of urban areas
D) Turbulence in the Earth's atmosphere which creates twinkling
E) Chromatic aberration due to use of only a single lens objective

Question 61

Which of the following greatly improves the angular resolution of radio maps?

A) Schmidt corrector plates
B) More sensitive spectrometers
C) Switching from film to CCD imaging
D) Use of interferometers
E) Chilling the infrared detectors

Question 62

The Earth's atmosphere is transparent to ________, as well as some radio and near-infrared wavelengths.

Question 63

The part of the electromagnetic spectrum with the shortest wavelengths is called ________.

Question 64

Knowing the peak emission wavelength of a blackbody allows you to determine its ________.

Question 65

The spectra of molecules are more complex because molecules can vibrate and ________ instead of just exhibiting electronic transitions like atoms.

Question 66

The product of the wavelength times the frequency of a wave is its ________.

Question 67

The design of modern X-ray telescopes depends on

A) lenses made of germanium.
B) the prime focus design, with mirrors made of iron.
C) grazing incidence optics.
D) achromatic lenses to keep the X-rays in focus.
E) the Cassegrain design, with mirrors made of lead.

Question 68

The Sun's blackbody curve peaks in the ________ portion of the spectrum.

Question 69

The longer the wavelength of the photon, the ________ the energy it carries.

Question 70

The gas between stars that has a temperature below a few hundred kelvins is best studies with which kind of telescope?

A) Radio
B) Infrared
C) Optical
D) Ultraviolet
E) X-ray

Question 71

________ is the scientific study of the distribution of electromagnetic waves by energy and how these patterns are created in atoms and molecules.

Question 72

________ is the color of the lowest frequency visible light.

Question 73

A typical space telescope is operated by how many astronauts?

A) 7
B) 5
C) 3
D) 1
E) 0

Question 74

The emission line for a given atom shows spectral features at the ________ location as in its absorption spectrum.

Question 75

In a wave, the distance from peak to peak is called the wave's ________.

Question 76

The colors of a neon light arise because it is a(n) ________ spectrum.

Question 77

Stars that appear blue or white in color are ________ than our yellow Sun.

Question 78

Advantages of radio astronomy include

A) radio waves are not scattered or deflected by Earth's atmosphere.
B) radio observations can be made even when the Sun is in the sky.
C) radio observations can be made even when the sky is obscured by clouds.
D) radio observations let astronomers study things that emit little visible light.
E) all of the above.

Question 79

Because the changes in energy levels happen in discrete steps, we refer to these as ________ leaps.

Question 80

In which part of the electromagnetic spectrum have astronomers been unable to get any information?

A) Gamma rays
B) X-rays
C) Ultraviolet
D) Microwaves
E) We now can access information in all spectral lengths.