Deck 3: Light and Telescopes

Question 1

In the seventeenth century, Isaac Newton suggested a particle theory for light and Christian Huygens proposed a wave theory. The present understanding is that

A) the wave theory is correct; the particle theory is not.
B) the particle theory is correct; the wave theory is not.
C) neither theory provides a correct description of light.
D) a combination of both theories is necessary to provide a correct description of light.

Answer 1

a combination of both theories is necessary to provide a correct description of light.

Question 2

The wavelength of green light is about 500 nanometers. What is this length in meters?

A) 500 thousandths of a meter
B) 500 trillionths of a meter (1 trillion = 1,000,000 million)
C) 500 millionths of a meter
D) 500 billionths of a meter (1 billion = 1000 million)

Answer 2

500 billionths of a meter (1 billion = 1000 million)

Question 3

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

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

Answer 3

James Clerk Maxwell

Question 4

Which wavelength region of the electromagnetic spectrum is taken up by visible light?

A) 1200 nm to 1500 nm
B) 4000 nm to 7000 nm
C) 400 nm to 700 nm
D) 100 nm to 400 nm

Question 5

If one sends white light through a prism to produce a spectrum, and then sends the red part of that spectrum through a second prism, the result will be

A) red.
B) yellow.
C) white.
D) black (no light).

Question 6

Electromagnetic radiation moving through space with the speed of light consists of oscillating

A) electric and magnetic fields moving in opposite directions along the same line in space.
B) magnetic fields that over time and distance change to oscillating electric fields and then back to magnetic fields in a continuous manner.
C) electric and magnetic fields with the same frequency and wavelength and traveling in the same direction.
D) electric fields, with magnetic fields occasionally accompanying them, moving in the same direction.

Question 7

Thomas Young demonstrated that light behaves as a wave by showing that

A) light striking a metal surface releases electrons from the metal, with violet light producing more energetic electrons than red light.
B) light passing through two narrow, closely spaced slits produces a pattern of light and dark bands on a screen by wave interference.
C) the speed of light in a vacuum is the same for all observers.
D) the speed of light decreases when it enters a denser, transparent medium.

Question 8

When light passes through a prism of glass,

A) the prism absorbs colors from different parts of the broad beam coming out of the prism, leaving the complementary colors seen.
B) different colors are caused by multiple reflections within the prism and the resulting interference between the beams.
C) refraction changes the directions of different colors or wavelengths of light.
D) the prism adds colors to different parts of the outgoing and broadly scattered beam.

Question 9

In the 1860s, James Clerk Maxwell carried out important investigations on the nature of light when he

A) demonstrated the wave nature of light by passing light through two slits and obtained a pattern of bright and dark bands on a screen that he correctly interpreted as interference between the two light beams.
B) demonstrated that white light was made up of colors that could be split by a prism and that these colors were not produced by the glass through which the light passed.
C) proved mathematically that light could be described by oscillating electric and magnetic fields.
D) showed that a prism through which light passed added a spectrum of colors to the light.

Question 10

If one sends white light through a prism to produce a spectrum, and then sends this entire spectrum through a lens to recombine it, the result will be

A) red.
B) yellow.
C) white.
D) black (no light).

Question 11

When visible light passes through a prism of glass, as shown in Figure 3-1, which wavelengths of light are deflected MOST by the glass?

A) longer wavelengths
B) intermediate wavelengths, the green color
C) All wavelengths are deviated by the same amount.
D) shorter wavelengths

Question 12

Visible wavelengths of electromagnetic radiation have a range of wavelengths of

A) 400 nm to 700 nm.
B) 1 nm to 100 nm.
C) 800 nm to 1900 nm.
D) 90 nm to 130 nm.

Question 13

In his double-slit experiment, Thomas Young used just a single color of light. Suppose he had used a mixture of two colors. What result would he have obtained?

A) The two waves would have canceled each other out, and he would have seen nothing. This is why he used only one color.
B) Two patterns would have formed, one on each color, exactly on top of each other.
C) Two similar patterns would have formed with the light of the shorter wavelength forming the more closely spaced pattern.
D) Two similar patterns would have formed with the light of the longer wavelength forming the more closely spaced pattern.

Question 14

When white light passes through a prism a spectrum is formed. This is because the prism

A) adds color to the light.
B) subtracts from the light, producing color.
C) causes different wavelengths of light to travel in different directions.
D) causes different parts of the light beam to vibrate at different frequencies.

Question 15

In 1801, Thomas Young performed a crucial experiment on the nature of light when he

A) demonstrated the wave nature of light by passing light through two slits and obtained a pattern of bright and dark bands on a screen that he correctly interpreted as interference between the two light beams.
B) proved mathematically that light could be described by oscillating electric and magnetic fields.
C) showed that a prism through which light passed added a spectrum of colors to the light.
D) demonstrated that white light was made up of colors that could be split by a prism and that these colors were not produced by the glass through which the light passed.

Question 16

Who first proved that light is a wave?

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

Question 17

One nanometer (nm) is

A) 10^-12 m.
B) 10^-6 m.
C) 10⁹ m.
D) 10^-9 m.

Question 18

Isaac Newton's prism experiment showed that when a beam of white light passes through a prism, the prism

A) adds color to the light.
B) subtracts from the light to allow the previously masked colors to appear.
C) changes the white light into something completely different so that it could not be reformed into white light.
D) causes different colors in the white light to be emitted in different directions.

Question 19

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

A) proved mathematically that light could be described by oscillating electric and magnetic fields.
B) demonstrated that white light was made up of colors that could be split by a prism and that these colors were not produced by the glass through which the light passed.
C) showed that a prism through which light passed added a spectrum of colors to the light.
D) demonstrated the wave nature of light by passing light through two slits and obtaining a pattern of bright and dark bands on a screen that he ascribed to interference between the two beams.

Question 20

In angstroms (Ǻ), the visible wavelengths of electromagnetic radiation have a range of

A) 40 Ǻ to 70 Ǻ.
B) 400 Ǻ to 700 Ǻ.
C) 4000 Ǻ to 7000 Ǻ.
D) 40,000 Ǻ to 70,000 Ǻ.

Question 21

The speed of light is

A) 3 × 10¹⁰ m/sec.
B) 3 × 10⁸ m/sec.
C) 3 × 10¹² m/sec.
D) 3 × 10⁵ m/sec.

Question 22

If a laser light pulse was sent toward the Moon and some of this light were to be reflected toward Earth from retroreflectors left on the Moon by astronauts, how long after the transmission of the initial flash would the reflected light be detected through a telescope on Earth?

A) 2.56 microseconds
B) 2.56 seconds
C) 1.28 seconds
D) 1.28 milliseconds

Question 23

One difference between violet light and red light is that

A) violet light travels faster than red light, even in a vacuum.
B) violet light has a shorter wavelength than red light.
C) violet light is hotter than red light.
D) photons of violet light have less energy than photons of red light.

Question 24

Violet light differs from red light in that it

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

Question 25

What is the relationship between color and wavelength for light?

A) Wavelength increases from violet to yellow-green, then decreases again to red.
B) Wavelength decreases from violet to red.
C) Wavelength increases from violet to red.
D) Wavelength depends only on brightness and is independent of color.

Question 26

Who first showed that light does not travel at infinite speed, and when did they show it?

A) Ole Rømer in 1675
B) Thomas Young in 1801
C) James Clerk Maxwell in 1864
D) Isaac Newton in 1704

Question 27

The average distance of Pluto from the Sun is 40 au. How long does it take for light to travel across the solar system from one side of Pluto's orbit to the other?

A) 5 ½ hours
B) 8 minutes
C) 22 hours
D) 11 hours

Question 28

The diameter of Earth is about 13,000 km. What distance does light travel in one second, in terms of the diameter of Earth?

A) 23 times the diameter
B) 23,077 times the diameter
C) 46 times the diameter
D) 0.043 times the diameter

Question 29

In 1675, Ole Rømer measured the speed of light by

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

Question 30

All forms of light have what property in common?

A) All forms of light are electromagnetic radiation.
B) All forms of light have the same wavelength.
C) All forms of light are ultrasonic radiation.
D) All forms of light have wavelengths between 400 nm and 700 nm.

Question 31

Approximately how long does it take light to travel from the fingertips of a person's extended arm to one's eye?

A) zero time because light is transmitted instantaneously
B) 2.5 trillionths of a second (2.5 × 10^-12 sec)
C) 2.5 billionths of a second (2.5 nanoseconds)
D) 2.5 millionths of a second (2.5 microseconds)

Question 32

Consider a beam of electromagnetic radiation of a single frequency. The energy of each photon in this beam depends on each these properties of the beam EXCEPT

A) wavelength.
B) frequency.
C) intensity.
D) color.

Question 33

When the Galileo spacecraft reached Jupiter on December 7, 1995, Jupiter was almost at conjunction with the Sun. Given that it takes 8 1/3 minutes for light to travel a distance of 1 au, how long did it take Galileo's signals to reach Earth from Jupiter? (A diagram might help to envision this configuration.)

A) 52 minutes
B) 35 minutes
C) 60 minutes
D) 43 minutes

Question 34

Suppose Rømer had used Saturn and one of its satellites instead of Jupiter and Io to measure the speed of light. How would his measurements have compared with those for Jupiter?

A) The measured time discrepancy between predicted and measured values for a given eclipse would have been shorter for Saturn.
B) The measured time discrepancy between predicted and measured values for a given eclipse would have been the same for Saturn.
C) The measured time discrepancy between predicted and measured values for a given eclipse would have been longer for Saturn.
D) Rømer could not have made such a measurement because Saturn had not yet been discovered.

Question 35

Suppose one tries to explain Rømer's measurements in the Ptolemaic model (adding the Galilean moons) with circular orbits and Earth in the center of the system. How could the differences in eclipse times be explained?

A) The later times would still occur when Jupiter is at conjunction and the earlier times when Jupiter is at opposition.
B) The later times would occur when Jupiter is moving westward with respect to the stars and the earlier times when Jupiter is moving eastward with respect to the stars.
C) The later times would occur when Jupiter is moving eastward with respect to the stars and the earlier times when Jupiter is moving westward with respect to the stars.
D) Jupiter in this model is the same distance from Earth at all times so no explanation is possible.

Question 36

Which method did Ole Rømer use to show that light did not travel at infinite speed?

A) Rømer observed that eclipses of Jupiter's satellites by the planet appeared to occur later when Earth was farther away from Jupiter because of the travel time for light over the extra distance.
B) Rømer measured a time delay between the instant that he sent a flash of light to a mirror on a distant hill and the return of the flash after reflection.
C) Rømer carried out a laboratory experiment in which a light beam was sent through an opaque, rotating disk with holes in it and reflected from a distant mirror, where the returning beam did not return through the same hole from which it left because of the travel time for light.
D) Rømer measured a 2 $1 / 2$ -second delay between the time of the outgoing pulse of light sent from Earth to the Moon and the time of the returning light pulse after reflection from the Moon.

Question 37

Suppose Ole Rømer had been able to make accurate speed-of-light measurements from the eclipses of Saturn's satellites as well as Jupiter's. How would these measurements have compared?

A) Calculations from the Saturn data should produce a larger value for the speed of light.
B) Calculations from the Saturn data should produce a smaller value for the speed of light.
C) The times for the Saturn eclipses should show larger discrepancies from the predicted values, but the calculated speed of light should be the same.
D) The times for the Saturn eclipses should show smaller discrepancies from the predicted values, but the calculated speed of light should be the same.

Question 38

How much time elapsed from when Ole Rømer discovered that light did not travel at infinite speed to a time when the speed of light was first measured accurately?

A) No time at all-it was Rømer himself who measured this speed accurately!
B) 28 years
C) almost 1000 years
D) more than a century but less than two centuries

Question 39

The speed of light in space is

A) infinite, traveling through space instantaneously.
B) variable, depending on the speed of its source, but very large (on average, 3 × 10⁸ meters per second).
C) 3 × 10¹⁰ meters per second, independent of the speed of the source.
D) 3 × 10⁸ meters per second, independent of the speed of the source.

Question 40

What prevented Ole Rømer from calculating an accurate value for the speed of light from his measurements of the delays in eclipse times of Jupiter's moons?

A) The dimensions of the solar system, particularly the length of 1 au, were not known very accurately.
B) Telescopes were not good enough at that time to show Jupiter's moons clearly, and accurate timings were not possible.
C) The distance between Earth's orbit and Jupiter's orbit was unknown.
D) The clocks available at that time were not sufficiently accurate.

Question 41

In the 1860s, Maxwell derived a set of mathematical equations that described electromagnetic waves that could have different wavelengths. These waves, which include visible light, have since been shown to

A) have no wavelength limit, either short or long.
B) have no upper wavelength limit, but waves cannot exist with wavelengths smaller than an atom.
C) have no short wavelength limit, but waves cannot exist with wavelengths longer than about the diameter of Earth.
D) exist only over a wavelength range from infrared to ultraviolet radiation.

Question 42

Our present understanding of the nature of light is that it

A) behaves only as a wave.
B) behaves only as a particle.
C) displays behavior of both waves and particles.
D) is completely different from both waves and particles.

Question 43

The idea that light consists of photons, bundles of pure energy, was first proposed by

A) Newton.
B) Rømer.
C) Young.
D) Einstein.

Question 44

In which one of these ranges of the electromagnetic spectrum do photons have the MOST energy?

A) infrared
B) visible
C) ultraviolet
D) All of them since all electromagnetic photons have the same energy.

Question 45

A beam of light of which of these pure colors is made up of photons of the lowest energy?

A) red
B) yellow
C) green
D) blue

Question 46

How does the wavelength of visible light compare to the wavelengths of other forms of electromagnetic radiation?

A) longer than ultraviolet but shorter than X-ray
B) longer than X-ray but shorter than gamma ray
C) longer than infrared but shorter than radio wave
D) longer than X-ray but shorter than radio wave

Question 47

Which of these sequences of electromagnetic radiation is correct, in order of increasing energy of the photons (or quanta)?

A) visible light, microwave, radio wave, infrared
B) radio wave, microwave, gamma ray, UV
C) visible light, UV radiation, X-ray, gamma ray
D) gamma ray, radio wave, X-rays, infrared

Question 48

A particular photon of ultraviolet (UV) light has a wavelength of 200 nm and a photon of infrared (IR) light has a wavelength of 2000 nm. What is the energy of the UV photon compared to that of the IR photon?

A) The UV photon has 1/10 of the energy of the IR photon.
B) The UV photon has 10 times more energy than the IR photon.
C) The UV photon has 1/100 of the energy of the IR photon.
D) The UV photon has 100 times more energy than the IR photon.

Question 49

The radio station has a broadcast frequency of 89.7 megahertz. What is the energy of a single photon in this radio beam (in joules)?

A) 1.03 × 10^-31
B) 5.98 × 10^-26
C) 4.95 × 10^-22
D) 2.86 × 10^-19

Question 50

What is the one fundamental difference between X-rays and radio waves?

A) X-rays and radio waves can only be produced by different sources.
B) The wavelengths of X-rays and radio waves are very different.
C) The speeds of X-rays and radio waves in outer space are different.
D) Radio waves are wavelike, whereas X-rays only behave like particles.

Question 51

Visible light occupies what portion of the full wavelength range of electromagnetic radiation?

A) a very narrow range
B) two narrow but separate ranges between ultraviolet and infrared radiations, the red and the blue, which mix to give all the other colors
C) about half of the possible range
D) almost the full range between radio and X-ray

Question 52

What is 3 × 10⁸ m/s divided by 500 nm?

A) 6 × 10⁵ meters per second
B) 6 × 10¹⁴ per second
C) 6 × 10⁷ meters per nanometer
D) 6 × 10¹⁴ meters per second

Question 53

A beam of light of which of these pure colors is made up of photons of the highest energy?

A) red
B) yellow
C) green
D) blue

Question 54

If two photons in a vacuum have different energies, what can be said about the wavelengths of the photons?

A) The higher-energy photon has the shorter wavelength.
B) The higher-energy photon has the longer wavelength.
C) The two photons have the same wavelength; all photons have the same wavelength, regardless of energy.
D) We cannot say anything; wavelength depends only on color, not on energy.

Question 55

In the photoelectric effect, a beam of light impinges on a metal, and it is observed that electrons are ejected from the metal in greater numbers as the

A) wavelength of the light is increased.
B) wavelength of the light is decreased.
C) intensity of the light is increased.
D) intensity of the light is decreased.

Question 56

The wavelength of infrared radiation is longer than the wavelength of visible light and is usually measured in units of micrometers. 1 micrometer (m) is

A) 10^-6 m.
B) 10^-3 m.
C) 10⁶ m.
D) 10^-9 m.

Question 57

The Lyman-alpha spectral line of hydrogen has a wavelength of 121.6 nm. In which wavelength band does this line occur?

A) ultraviolet
B) visible light
C) Infrared
D) X-ray

Question 58

Visible light occupies what position in the electromagnetic spectrum?

A) between radio and infrared radiation
B) between infrared and ultraviolet
C) between infrared and microwave
D) between ultraviolet and X-ray

Question 59

In which these parameters does a photon of blue light NOT differ from a photon of yellow light in a vacuum?

A) energy
B) color
C) wavelength
D) speed

Question 60

A particular photon has a wavelength of 450 nm, and a second one has a wavelength of 580 nm. Which of these statements about the energies of these two photons is true?

A) All photons have the same energy, regardless of wavelength.
B) The 450-nm photon has the higher energy.
C) The 580-nm photon has the higher energy.
D) The photon from the higher-intensity light source has the higher energy (regardless of wavelength).

Question 61

Which of these lists of different types of electromagnetic radiation is correctly ordered in wavelength, from shortest to longest?

A) gamma ray, ultraviolet, radio, infrared
B) radio, ultraviolet, infrared, gamma ray
C) radio, infrared, ultraviolet, gamma ray
D) gamma ray, ultraviolet, infrared, radio

Question 62

Which of these statements is true?

A) Visible light takes up only a very small part of the total range of wavelengths in the electromagnetic spectrum.
B) Visible light takes up the whole electromagnetic spectrum.
C) Visible light takes up most (but not all) of the total range of wavelengths in the electromagnetic spectrum.
D) Visible light is not part of the electromagnetic spectrum.

Question 63

Radio waves travel through space at what speed?

A) much faster than the speed of light
B) at the speed of light, 3 × 10⁸ m/s
C) much slower than the speed of light
D) slightly faster than the speed of light because their wavelength is longer

Question 64

An electrical spark, such as lightning, generates electromagnetic radiation over a wide range of wavelengths. How much longer will a pulse of radio energy take to travel between two detector stations 100 m apart than will a pulse of ultraviolet radiation from the same spark?

A) The time will be identical because both pulses travel at the speed of light.
B) Just a little longer because the high frequency UV radiation travels faster than the low frequency radio waves.
C) A much shorter time because long wavelength radiation travels faster.
D) A much longer time because radio waves have much longer wavelengths and therefore travel slower.

Question 65

If a person creates a spectrum with a prism as Newton did and then probes the temperature with thermometers that they have kept in the dark, they will find the thermometer will show a temperature rise when placed

A) in the visible part of the spectrum but nowhere else.
B) in the visible part of the spectrum and in the invisible region just beyond the red but nowhere else.
C) in the visible part of the spectrum and in the invisible region just beyond the violet but nowhere else.
D) anywhere from the invisible region beyond the red, through the visible, through the invisible region beyond the violet.

Question 66

The two ranges of electromagnetic radiation for which Earth's atmosphere is reasonably transparent are

A) X- ray and visible light.
B) visible light and radio wave.
C) visible light and far infrared radiation.
D) UV radiation and radio wave.

Question 67

Suppose an astronomical satellite observes the Crab Nebula at a wavelength of 0.85 nm. In what wavelength range is this satellite observing?

A) X-ray
B) ultraviolet
C) Infrared
D) gamma ray

Question 68

Which of these types of electromagnetic radiation has the longest wavelength?

A) radio wave
B) ultraviolet light
C) infrared
D) microwave

Question 69

Which of these wave effects is NOT electromagnetic in nature?

A) gamma rays
B) seismic waves
C) microwaves
D) radio waves

Question 70

An electromagnetic wave has a wavelength of 80 cm. This wave is

A) visible light.
B) ultraviolet radiation.
C) infrared radiation.
D) a radio wave.

Question 71

Which of these wave effects is electromagnetic?

A) gravitational wave
B) cosmic ray proton
C) microwave
D) sound wave

Question 72

X-rays and visible light are

A) different because X- rays are made up of waves, whereas light is made up of particles.
B) different because X-rays are made up of particles, whereas light is made up of waves.
C) the same thing except that X-rays have longer wavelengths than visible light.
D) the same thing except that X-rays have shorter wavelengths than visible light.

Question 73

Which of these types of electromagnetic radiation has the shortest wavelength?

A) visible light
B) X-ray
C) ultraviolet
D) gamma ray

Question 74

Earth's atmosphere is transparent to which of these types of electromagnetic radiations?

A) X-ray
B) radio wave
C) long infrared wavelength
D) short ultraviolet wavelength

Question 75

Electromagnetic radiation emitted by a planet has a wavelength of 10 micrometers (1 m = 10^-6 m). What name is given to this type of electromagnetic radiation?

A) gamma ray
B) infrared
C) radio
D) visible light

Question 76

Which of these can travel at the speed of light in a vacuum?

A) visible light, radio waves, X-rays, and gamma rays
B) only visible light; all other electromagnetic waves travel slower than the speed of light.
C) visible light, atoms, X-rays, and subatomic particles (e.g., electrons)
D) visible light, infrared radiation, ultraviolet radiation, and subatomic particles (e.g., electrons)

Question 77

Which of these wavelength regions must be observed from space because almost no energy in this region reaches the ground?

A) radio
B) infrared
C) X-rays
D) visible light

Question 78

Who was one of the first astronomers to build and use a telescope to observe the night sky?

A) Galileo
B) Copernicus
C) Tycho Brahe
D) Newton

Question 79

In terms of wavelengths, gamma rays

A) have the shortest wavelengths of the named electromagnetic waves.
B) are intermediate, between X-rays and ultraviolet waves.
C) are intermediate, between radio and infrared waves.
D) have the longest wavelengths of the named electromagnetic waves.

Question 80

Suppose an astronomical satellite observes the Orion Nebula at a wavelength of 1250 nm. In what wavelength range is this satellite observing?

A) X-ray
B) ultraviolet
C) infrared
D) visible light