Deck 2: Decoding the Hidden Messages in Starlight

Question 1

The first recorded experiment on passing light through a glass prism was performed by Isaac Newton.

Answer 1

True

Question 2

X-rays are a form of light and,because of this,will travel at the speed of light.

Answer 2

True

Question 3

Who first demonstrated that light does NOT travel at infinite speed?

A) Isaac Newton
B) Ole Rømer
C) James Clerk Maxwell
D) Joseph von Fraunhofer

Answer 3

Ole Rømer

Question 4

Light has properties of both waves and particles.

Question 5

Sunlight is made of a mixture of all colors that can be spread out into a spectrum.

Question 6

Galileo was able to determine a precise value of the speed of light by using a technique that involved shuttered lanterns and his assistant on a different hill of known distance.

Question 7

How much energy a star emits is determined by both temperature and surface area.

Question 8

The Compton Gamma Ray Observatory was designed to capture intense energy bursts from black holes and the merging of neutron stars.

Question 9

The atmosphere is transparent to most radio waves.

Question 10

The wavelength of the maximum emission of an object depends only on the size of an object.

Question 11

Isaac Newton was the first person to offer an explanation of light as being in the form of waves.

Question 12

Infrared light allows astronomers to view warm stars in clouds of dust and gas that are not viewable in visible light.

Question 13

The Doppler effect is an important tool in astronomy because it uncovers basic information about the temperature of objects in space.

Question 14

Our eyes can only see a small band of the entire spectrum of light.

Question 15

As the frequency of light increases,the wavelength of light also increases.

Question 16

A hot,transparent gas produces a continuous spectrum.

Question 17

Electrons can jump only to specific orbits with certain energy levels within atoms.

Question 18

According to Einstein's special theory of relativity,nothing can travel faster than the speed of light.

Question 19

A blackbody curve graphs brightness of a star over time.

Question 20

The successor of the Hubble Space Telescope is the James Webb Space Telescope.

Question 21

Which of the following is an electromagnetic wave?

A) Microwave
B) Gravitational wave
C) Cosmic-ray proton
D) Sound wave

Question 22

On the absolute scale of temperature (in kelvins),the zero of the scale corresponds to the

A) freezing point of hydrogen.
B) melting point of ice.
C) mean temperature of space.
D) temperature at which motions of atoms and molecules essentially cease.

Question 23

What kind of light has the lowest energy?

A) X-ray
B) Ultraviolet
C) Radio
D) They all have the same energy

Question 24

How far apart from each other would Galileo and his assistant had to have been in order for the round-trip time of their beam of light to equal 1 second?

A) 1500 km
B) 15,000 km
C) 150,000 km
D) 150,000,000 km

Question 25

The Kelvin scale measures

A) temperature referenced to zero at the freezing point of water.
B) mass per unit volume,or density,with water having a value of 1.0.
C) temperature in Fahrenheit-sized degrees above absolute zero.
D) temperature in Celsius-sized degrees above absolute zero.

Question 26

Around 1800,William Herschel passed light through a prism and discovered that part of the NONVISIBLE radiation in the resulting spectrum would raise the temperature of a thermometer.This portion of the electromagnetic spectrum is

A) radio.
B) infrared.
C) ultraviolet.
D) X-ray.

Question 27

Visible light occupies which position in the whole electromagnetic spectrum?

A) Between radio and infrared radiation
B) Between ultraviolet and X-rays
C) Between infrared and ultraviolet
D) Between infrared and microwave

Question 28

When light passes through a prism of glass,the

A) different colors are caused by multiple reflections in the prism and interference between the resulting beams.
B) prism absorbs colors from different parts of the broad beam coming out of the prism,leaving the complementary colors that we see.
C) prism adds colors to different parts of the broadly scattered beam coming out of it.
D) different colors or wavelengths of light are separated in angle by the prism.

Question 29

Violet light differs from red light in that violet light

A) has a longer wavelength than red light.
B) travels more slowly (through a vacuum)than red light.
C) travels more quickly (through a vacuum)than red light.
D) has a shorter wavelength than red light.

Question 30

Radio waves travel through space at what speed?

A) Much faster than the speed of light
B) Faster than the speed of light because their wavelength is longer
C) Slower than the speed of light
D) At the speed of light,3 × 10⁸ m/s

Question 31

In 1675,Rømer measured the speed of light by

A) timing eclipses of Jupiter's satellites,which appeared to occur later when Earth was farther from Jupiter.
B) measuring how long it took the light from stars located at different distances to reach Earth.
C) reflecting light from a mirror rotating at a known speed and measuring the angle of deflection of the light beam.
D) opening a shutter on a lantern on a hilltop and measuring the time taken for light from an assistant's shuttered lantern to return.

Question 32

In terms of wavelengths,gamma rays are

A) the shortest wavelength electromagnetic waves.
B) intermediate between radio and infrared waves.
C) intermediate between X-rays and ultraviolet waves.
D) the longest wavelength electromagnetic waves.

Question 33

The first reliable method developed to measure the speed of light involved

A) careful observation of the motions of the moons of Jupiter at different times in Jupiter's orbit.
B) observing the opening and closing of shutters on lanterns on hilltops separated by a known distance.
C) bouncing a beam of light off several different mirrors.
D) making careful measurements of the orbital path of the Moon around Earth.

Question 34

Around 1670,Isaac Newton performed a crucial experiment on the nature of light when he

A) showed the wave nature of light by passing light through two slits and obtaining a pattern of bright interference bands on a screen.
B) showed that light that passes through a prism has a spectrum of colors added to it by the prism.
C) proved mathematically that light can be described by oscillating electric and magnetic fields.
D) demonstrated that the colors that make up white light are intrinsic,not produced by the glass through which the light passes.

Question 35

Who first proved that light is a wave?

A) James Clerk Maxwell
B) Albert Einstein
C) Isaac Newton
D) Thomas Young

Question 36

Which has the greatest energy?

A) Infrared light
B) Visible light
C) Ultraviolet light
D) They all have the same energy.

Question 37

White light passes through a prism and separates into a spectrum of colors.All of these colors are recombined into a single beam by means of a lens.What color is this beam?

A) White
B) Black (there will be no light left)
C) It will be in the ultraviolet region of the spectrum.
D) It will be in the infrared region of the spectrum.

Question 38

Who performed an experiment with an assistant at night on two hilltops a known distance apart with lanterns to try to measure the speed of light?

A) Aristotle
B) Galileo
C) Newton
D) Einstein

Question 39

What is the wavelength of radiation emitted by an FM radio station transmitting at a frequency of 100 MHz (or 10⁸ Hz)?

A) 300 m
B) 0.03 m
C) 1 m
D) 3 m

Question 40

Who was the first person to suggest that light is an electromagnetic wave?

A) Albert Einstein
B) Thomas Young
C) Isaac Newton
D) James Clerk Maxwell

Question 41

The gas in interstellar space between the stars is very tenuous ("thin").Near a hot star,this gas is heated to a high temperature.Any such hot,tenuous gas emits light

A) at all wavelengths,peaking at a certain wavelength or color.
B) at no wavelength,because hot thin gases do not emit light.
C) only at specific wavelengths ("spectral lines"),and these spectral lines do not change in wavelength as the temperature changes.
D) only of specific colors ("spectral lines")whose wavelengths change as the temperature changes.

Question 42

The human eye has evolved over time so that its peak wavelength sensitivity is about 0.5 $\mu$ m (1 $\mu$ m = 10^-6 m).Use Wien's law to calculate the temperature of blackbody radiation to which the eye is most sensitive.

A) 14,240 K
B) 0.58 K
C) 580 K
D) 5800 K

Question 43

The total energy emitted per unit time at all wavelengths from an object increases by what factor if its temperature is increased by a factor of 3 (e.g. ,from room temperature to 900 K)?

A) 27
B) 81
C) 3
D) 9

Question 44

A typical but very cool star might have a temperature of 3100°C.On the Kelvin scale,this is about

A) 2827 K.
B) 3068 K.
C) 3373 K.
D) 3100 K,because Kelvin and Celsius degrees are the same.

Question 45

The chemical makeup of a star's surface is obtained by

A) measuring the chemical elements present in the stellar wind.
B) theoretical methods,considering the evolution of the star.
C) taking a sample of the surface with a space probe.
D) spectroscopy of the light emitted by the star.

Question 46

Spectral lines are of particular importance in astronomy because

A) each different element has a characteristic line spectrum.
B) they can be observed through a diffraction grating.
C) they are the only light bright enough to be seen at large distances.
D) only stars produce bright line spectra.

Question 47

The early workers in spectroscopy (Fraunhofer with the solar spectrum;Bunsen and Kirchhoff with laboratory spectra)discovered what very significant fact about the spectra produced by hot gases,such as elements heated in a flame?

A) The higher the temperature,the greater the proportion of red in the emitted spectral lines.
B) They produce their own characteristic pattern of spectral lines,which remain fixed as the temperature increases.
C) They emit spectral lines that move continuously toward the blue end of the spectrum as the gas temperature increases.
D) They produce the same set of spectral lines and are hence indistinguishable.

Question 48

A metal rod is heated in a flame.It is at its hottest when the color of the rod glows

A) red.
B) orange.
C) yellow.
D) red-orange.

Question 49

The hot,dense gas existing in the Sun emits energy

A) at all wavelengths uniformly.
B) at all wavelengths,with a peak at one particular wavelength (color).
C) only at certain wavelengths and no others.
D) mostly at the longest and shortest wavelengths,less in between.

Question 50

The setting Sun appears red because

A) its light is scattered by a thicker layer of air than during the day.
B) red light is more refracted around the horizon than is blue light.
C) the Sun is cooler in the evening.
D) red light is more diffracted around the horizon than is blue light.

Question 51

The star Vega has a higher surface temperature than the Sun;therefore (with IR = infrared and UV = ultraviolet),

A) Vega emits less IR and more UV flux than the Sun.
B) Vega emits less IR and less UV flux than the Sun.
C) Vega emits more IR and less UV flux than the Sun.
D) Vega emits more IR and more UV flux than the Sun.

Question 52

What changes would you expect to see in the resulting spectrum of emitted light from a piece of metal when it is heated slowly in an intense flame from 500 K to 1500 K?

A) The intensity of radiation would decrease and the color would remain the same.
B) The intensity of radiation would increase and its color would change from red through orange toward yellow.
C) The intensity of radiation would increase,and the color would remain the same.
D) The intensity of radiation would remain constant,while the color would change from yellow to orange and red.

Question 53

A scientist measures the temperature change between freezing water and boiling water with a thermometer calibrated in the Kelvin or absolute scale.How many degrees kelvin (K)will he measure?

A) 180
B) 273
C) 373
D) 100

Question 54

If a certain gas is heated and observed through a grating,a bright line spectrum will be seen.If,instead,a source of continuous spectrum shines through a cooler sample of this same gas,a dark absorption spectrum is observed.How do the positions of the lines in these two spectra compare?

A) All of the lines in the spectrum from the hot gas will be at higher frequencies than the corresponding lines in the spectrum of the cooler gas.
B) All of the lines in the spectrum from the hot gas will be at lower frequencies than the corresponding lines in the spectrum of the cooler gas.
C) The lines in the two spectra will be at the same frequencies.They will be the same spectra.
D) These two processes produce spectra by completely different means,and there will be no relationship at all between the two spectra.

Question 55

The "color" or wavelength of maximum emission of radiation for a hot,solid body (or a dense gas such as a star)when the body cools from a temperature of several thousand degrees

A) remains fixed,as the light fades and eventually becomes invisible to the eye.
B) moves toward the red end of the spectrum.
C) moves toward the blue end of the spectrum.
D) remains absolutely constant,depending only on the original color of the body.

Question 56

Why is the sky blue?

A) The air molecules absorb red light better than blue light,allowing more blue light to reach our eyes.
B) The air molecules scatter blue light better than red light,so more blue light reaches our eyes.
C) The air molecules scatter red light better than blue light,so less red light reaches our eyes.
D) The air molecules absorb blue light better than red light,making the sky appear bluer.

Question 57

Atoms in a hot,low-density gas (e.g. ,in a laboratory-type spectral source)emit a spectrum that is

A) a series of specific colors at the same wavelengths,independent of the type of atom excited.
B) a series of specific colors,whose positions change as the gas temperature changes.
C) continuous over all visible wavelengths,with maximum intensity in the blue.
D) a series of specific colors,unique to the type of atom in the tube,but fixed in position even when the gas temperature changes.

Question 58

The energy flux F from a star is the

A) amount of visible light energy emitted by each square meter of the star's surface each second.
B) amount of energy emitted by each square meter of the star's surface each second.
C) total energy emitted by the star over its lifetime.
D) amount of energy emitted by the entire star each second.

Question 59

An astronomer studying a particular object in space finds that the object emits light only in specific,narrow emission lines.The correct conclusion is that this object

A) cannot consist of gases but must be a solid object.
B) is made up of a hot,dense gas surrounded by a rarefied gas.
C) is made up of a hot,dense gas.
D) is made up of a hot,low-density gas.

Question 60

Chemical pollution often results in large numbers of very small particles being emitted into the atmosphere.What effect,if any,will this have on the color of the sunset?

A) It should have no effect.
B) It should make the sunset look less red.
C) It should make the sunset look more red.
D) Its effect depends on the color of the pollutants.

Question 61

The main optical element in a refracting telescope is a

A) lens.
B) mirror.
C) combination of many small plane mirrors.
D) prism of glass.

Question 62

The basic makeup of an atom is

A) small,negatively charged particles orbiting around a central positive charge.
B) negative and positive charges mixed uniformly over the volume of the atom.
C) small,positively charged particles orbiting around a central negative charge.
D) miniature planets,possibly with miniature people,gravitationally bound in orbits around a miniature star.

Question 63

The light-gathering power of a telescope is related directly to the

A) image quality of its optics (resolution).
B) area of its primary mirror or lens.
C) focal length of its primary mirror or lens.
D) ratio of the focal lengths of its primary element (mirror or lens)and its eyepiece.

Question 64

Why was adaptive optics developed?

A) To prevent distortion of mirrors by the vacuum of space
B) To prevent distortion by sagging in very thin,lightweight mirrors
C) To compensate for spherical aberration
D) To compensate for image distortion caused by Earth's atmosphere

Question 65

According to the Doppler effect,

A) the wavelength of light is shifted to a shorter wavelength if the source of light is moving toward you.
B) the wavelength of light is shifted to a longer wavelength if the source of the light is moving toward you.
C) the wavelength of peak emission of light from a source changes as the temperature of the source changes.
D) spectral lines are split into two or more wavelengths when the source of the light is in a strong magnetic field.

Question 66

The observed change in wavelength due to the Doppler effect occurs

A) whenever the light source is moving with respect to the observer (regardless of direction).
B) only when the light source has a radial velocity (toward or away from the observer).
C) only when the temperature of an object changes.
D) only when the light source has a proper motion (across the line of sight).

Question 67

When an object is moving toward you,the visible radiation that it emits is Doppler shifted toward the

A) ultraviolet.
B) infrared.
C) microwave.
D) radio.

Question 68

When astronomers look for evidence of hydrogen gas in the spectra of the Sun,the planets,and nearby stars,the positions of the spectral features or "lines" due to hydrogen

A) are in a very different pattern,depending on the location of the planet or star,and are reproduced only with difficulty in the laboratory.
B) are always in the same pattern,characteristic of hydrogen gas,as seen in the laboratory.
C) change systematically,depending on the distance from the source,starting with a laboratory pattern.
D) are in the same pattern for solar and planetary sources but are very different for stars at larger distances because of absorption of light by the interstellar matter.

Question 69

A typical refracting telescope is made up of

A) a long-focal-length lens at the front and a short-focal-length lens at the rear (next to your eye as you look through the telescope).
B) a short-focal-length lens at the front and a long-focal-length lens at the rear (next to your eye as you look through the telescope).
C) a mirror that gathers and focuses the light,and a lens next to your eye to examine the image.
D) two mirrors: one concave in shape and the second convex in shape.

Question 70

Normal human body temperature is about how much in the Kelvin scale?

A) 37 K
B) 100 K
C) 310 K
D) 1000 K

Question 71

A particular reflecting telescope has an objective mirror with a focal length of 1.2 m and an eyepiece lens of focal length 6 mm.What is the magnifying power of this telescope?

A) 5×
B) 2000×
C) 20×
D) 200×

Question 72

Which of the following does NOT represent a major drawback when developing a refracting telescope for astronomy?

A) Lenses cannot be made with focal lengths that produce very high magnifications.
B) Glass lenses are not completely transparent to certain kinds of light,restricting the observable wavelength range.
C) The lens brings different wavelengths of light to a focus at different positions.
D) The presence of defects in the glass lens through which the light must pass causes some of the light to scatter out of the beam.

Question 73

The spectrum of a star shows an equivalent set of dark absorption lines to those of the Sun,with one exception: Every line appears at a slightly longer wavelength,shifted toward the red end of the spectrum.What conclusion can be drawn from this observation?

A) The star is moving rapidly toward Earth.
B) A cloud of dust surrounds the star and absorbs the light.
C) The star is moving rapidly away from Earth.
D) The temperature of the star's surface is higher than that of the Sun.

Question 74

The specific colors of light emitted by an atom in a hot,thin gas (e.g. ,in a tube in a laboratory or a gas cloud in space)are caused by

A) the vibrations of the electrons within the atom.
B) an electron dropping into the nucleus and causing changes in the energy of the nucleus.
C) electrons jumping to lower energy levels,losing energy as they do so.
D) protons jumping from level to level.

Question 75

The major reason astronomers seek funds to build larger telescopes is to

A) bring stars closer to Earth.
B) measure a wider spectrum of light from stars.
C) provide magnified images of stars.
D) collect more light from distant objects.

Question 76

A department store sells an "astronomical telescope" with an objective lens of 30 cm focal length and an eyepiece lens of focal length 5 mm.What is the magnifying power of this telescope?

A) 150×
B) 6×
C) 15×
D) 60×

Question 77

How can you increase the magnification of a refracting telescope without decreasing the light-gathering power?

A) Decrease both the diameter and the focal length of the objective lens.
B) Increase the focal length of the eyepiece.
C) Decrease the focal length of the eyepiece.
D) Increase the diameter of the eyepiece.

Question 78

Electrons in atoms

A) occupy levels whose energies are fixed.
B) can have any energy.
C) cannot interact with light.
D) can only absorb light.

Question 79

By what factor is the amount of light gathered by the 10-m diameter Keck telescope on Mauna Kea,Hawaii,greater than that gathered by the 2.5-m diameter Mount Wilson telescope?

A) 4
B) 16
C) 256
D) 2

Question 80

In many instances,the detector that has replaced the photographic plate for astronomical photography is the

A) diffraction grating.
B) CCD (charge-coupled device).
C) interferometer.
D) PMT (photomultiplier tube).