Exploring the Cosmos - Mapping the Universe
1. Which of the following statements correctly describes the wavelength of an electromagnetic wave?
The wavelength is the distance between a trough and a peak.
The wavelength is the distance between two consecutive peaks.
The wavelength is the distance travelled by the wave in a short time.
The wavelength is the distance travelled by the wave in 1 second.
2. Why does a light ray bend when it crosses the boundary between two different media at an oblique angle?
Because the frequency increases.
Because the speed of light changes.
Because it interferes with the surface.
Because the amplitude is reduced.
3. A Newtonian telescope has
a flat secondary mirror
a correction plate
a diverging secondary mirror
just the primary mirror
4. As light passes from one medium to another, its direction of travel changes. What is the name of this effect?
Refraction
Interference
Dispersion
Diffraction
5. Diffraction gratings are used to
break up light into a spectrum.
detect infrared radiation.
increase the resolution of telescopes.
reduce diffraction of telescopes.
6. The speed of light in glass is
the same as in vacuum
reduced by approximately 60%
increased by approximately 50%
reduced by approximately 1%
7. Diffraction gratings are used for
reducing the diffraction of telescopes.
increasing the angular resolution of telescopes.
analysing the light spectrum.
detecting microwave radiation.
8. Which of the following parameters is the same for all electromagnetic waves propagating in a vacuum?
Speed
Wavelength
Amplitude
Colour
9. Which of the following parameters is the same for all electromagnetic waves propagating in a vacuum?
Colour
Amplitude
Speed
Wavelength
10. Why does a light ray bend when it crosses the boundary between two different media at an oblique angle?
Because the speed of light changes.
Because the frequency increases.
Because the amplitude is reduced.
Because it interferes with the surface.
11. A Newtonian telescope has
a diverging secondary mirror.
a correction plate.
just the primary mirror.
a flat secondary mirror.
12. The Hubble telescope was placed in space in order
to not be limited by the Earth’s horizon.
to improve the magnification.
to not be limited by the Earth’s atmosphere.
to be close to the stars.
13. An electromagnetic wave with a wavelength of 600 nm is
visible radiation.
infrared radiation.
ultraviolet radiation.
microwave radiation.
14. Which of the following uses a grazing incidence telescope?
International Space Observatory.
International Ultraviolet Explorer.
International Space Station.
Chandra X-ray satellite.
15. The angle through which a ray of light is bent by a glass prism depends on the
brightness of the light.
photoelectric effect.
wavelength of the light.
reflectivity of the prism.
16. The focal length of an ideal mirror depends on
brightness of the light.
reflectivity of the prism.
photoelectric effect.
wavelength of the light.
17. Light can be described as having a “dual†nature. What does this mean?
Light behaves like a wave and like a particle.
Light can be expressed as brightness and colour.
Light goes slow and fast.
If light moves in one direction, then it moves in the opposite direction also.
18. What is the angular size of the Moon?
5 degrees
0.5 degrees
0.5 arcminutes
0.5 arcseconds
19. Which of the following space-based telescopes detected water in the Orion nebula?
Chandra
The International Space Observatory (ISO)
Hubble
The International Ultraviolet Explorer (IUE)
20. If the width of the objective of a telescope is doubled, what happens to its light gathering power?
The light gathering power increased by a factor of four.
The light gathering power is decreased by a factor of four.
The light gathering power is increased by a factor of two.
The light gathering power remains the same.
21. For a telescope the objective focal length is 80 cm and the eyepiece focal length is 2 cm, what is the magnification?
40
160
less than 1
78
22. To detect dim objects a telescope needs
high resolution.
a long tube.
high magnification.
large diameter.
23. A Charge Coupled Device is used in telescopes to
reduce the effect of segmentation of mirrors.
improve light gathering.
compensate for sagging of the mirror.
detect light.
24. Long Baseline Interferometry is a technique often used in radio astronomy to
remove the effect of Cerenkov radiation.
improve the resolution of objects.
reduce the effect of light pollution in urban skies.
image neutrinos.
25. Karl Jansky was the pioneer of
radio astronomy.
optical astronomy
infra-red astronomy.
UV astronomy.
26. The LIGO gravitational wave detectors
have arm lengths of 600 m.
are bar detectors.
have arm lengths of 4 km.
are currently under construction.
27. Cerenkov radiation is given off when
an electron recombines with an ionised atom
an electron is ionised from an atom
a particle is travelling slower than the speed of light in a medium
a particle is travelling faster than the speed of light in a medium
28. Why is the colour of the sun during sunset red?
The sun changes its colour in 24 h from blue to red and back to blue.
The scattering of blue light is stronger than red light.
The diffraction of light is different. Blue light is more strongly diffracted.
The refraction of light is different. Blue light is more strongly refracted.
29. Which of the following processes is responsible for the absorption of Infra-Red radiation?
Excitation of vibrational modes of molecules.
Infra-Red radiation is not absorbed.
Breaking of the chemical bonds.
Splitting of the atomic nuclei.
30. The ISO satellite is sensitive to
X-rays.
UV.
IR.
Gamma rays.
31. The objective of a telescope is
the adaptor between the telescope and the human eye.
the part of it which first converges the light.
the reason why that telescope has been buil
the object under observation.
32. As light passes from one medium to another, its direction of travel changes. What is the name of this effect?
Interference
Refraction
Dispersion
Diffraction
33. How does an infrared telescope make detections?
By directly detecting the number of incident photons.
By monitoring changes in temperature caused by incident photons.
By monitoring the number of electrons released by incident photons.
By detecting oscillating electric signals generated by incident photons.
34. Which of the following processes is responsible for absorption of infrared radiation by the atmosphere?
The excitation of the vibrational modes of water vapour molecules.
Interaction of the radiation with the nuclei of atoms in the atmosphere.
The breaking of chemical bonds in ozone.
Conduction in an upper part of the atmosphere.
35. The twinkling of the stars is due to
refraction.
absorption.
scattering.
diffusion.
36. A Charge Coupled Device is used in telescopes to
improve light gathering.
detect light.
compensate for sagging of the mirror.
reduce the effect of segmentation of mirrors.
37. The Spitzer satellite uses
a Schmidt-Cassegrain design
a grazing incidence mirror
a prime focus arrangement
a Cassegrain design
38. The ISO satellite is sensitive to
Gamma rays.
X-rays.
IR.
UV.
39. Why are neutrinos so hard to detect in astronomical observatories?
There are no astronomical sources of neutrinos.
Neutrinos are absorbed in the upper atmosphere.
The neutrinos interact only weakly.
The neutrinos decay before reaching the Earth.
40. The Chandra Observatory is an observatory for
Radio astronomy.
X-Ray astronomy.
Neutrino astronomy.
Infra-red astronomy.
41. Why are astronomers interested in different parts of the spectrum?
The results would otherwise interfere destructively.
Different parts of the spectrum contain different information.
At some locations at the sky certain detectors do not work.
The different colours are nice.
42. An electromagnetic wave having a wavelength of 550 nm is:
ultra-violet radiation.
infrared radiation.
visible radiation.
gamma radiation.
43. Karl Jansky was the pioneer of
infra-red astronomy.
UV astronomy.
radio astronomy.
optical astronomy.
44. A grazing incidence mirror is used to focus
visible light.
gamma rays.
gravitational waves.
x-rays.
45. Modern observatories are placed on mountains
to be able to observe X-rays
to reduce the amount of turbulent atmosphere
because it is cheaper to build them on mountains
to get closer to the stars
46. The Super Kamiokande Neutrino observatory
is located underground in the USA
is a future planned detector in Japan
is located in the Mediterranean sea
is located underground in Japan
47. Cerenkov radiation is given off when
a particle is travelling slower than the speed of light in a medium
an electron is ionised from an atom
an electron recombines with an ionised atom
a particle is travelling faster than the speed of light in a medium
48. The typical sensitivity of interferometric gravitational wave detectors is of the order
1 millimeter
1 nanometer
1 attometer
1 micrometer
49. The Compton Gamma Ray Observatory
has imaging CCDis
has instruments to look at multiple energy bands
has grazing incidence mirrors to focus the high energy gamma rays
uses a large tank of water as a scintillation detector
50. Radio telescopes
do not require a very smooth surface.
need to be cooled.
require a very smooth surface.
operate only at night.
51. LIGO is an acronym for:
Laser Interferometric Gravitational-wave Observatory.
Light Ingoing Ground Observations.
Light Incident Gravitational Observation.
Laser Incoming Ground Observation.
52. Long Baseline Interferometry is a technique often used in radio astronomy to
reduce the effect of light pollution in urban skies.
improve the resolution of objects.
image neutrinos.
remove the effect of Cerenkov radiation.
53. Chromatic aberration can occur in a telescope because
the telescope is not stable.
light of different wavelengths are focussed to different positions.
the atmosphere is not stable.
light of different wavelengths are reflected to different positions.
54. The speed of light in a vacuum is approximately
30 million metres per second.
300 thousand metres per second.
30 thousand metres per second.
300 million metres per second.
55. The term 'refraction' is used to describe when light
waves add together to produce brighter light.
changes frequency when transmitting through different media.
changes direction when transmitting through different media.
bends around the edges of objects.
56. For an astronomical source, the focal length of a mirror is
the diameter of the mirror.
the thickness of the mirror.
the distance from the mirror to an object.
the distance from the mirror to the focal point.
57. Light can be described as having a "dual" nature. What does this mean?
It travels in two directions at the same time.
It behaves like a wave and a particle.
It can go fast and slow.
It has brightness and wavelength.
58. A Newtonian telescope is
a Cassegrain telescope.
a reflecting telescope.
a refracting telescope.
a prime focus telescope.
59. Astronomers hope to discover gravitational waves by
placing radio telescopes in space.
using highly-sensitive CCD sensors.
using laser interferometers.
detecting high-energy gamma rays.
60. During the day the sky appears blue because
the atmosphere reflects more red light from the Sun during the day.
blue light is refracted less than red light.
the Sun changes colour over a period of 24 hours.
the scattering of blue light is stronger than red light.
61. Atmospheric absorption causes
the stars to twinkle in appearance.
the scattering of light with large wavelengths.
the light from stars to appear stronger than it should.
dimming or extinction of certain wavelengths of light.
62. The resolving power of a radio telescope can be increased by
decreasing the diameter of the primary mirror.
putting the telescope on a mountain.
increasing the diameter of the primary mirror.
making observations during the night.
63. A Schmidt-Cassegrain telescope is one that has?
A corrector plate, a primary mirror and a secondary mirror.
Only lenses.
Only mirrors.
A corrector plate and a primary mirror only.
64. Why are astronomers interested in measuring light at different parts of the electromagnetic spectrum?
Because in vacuum light travels at different speeds at different wavelengths.
Because visible light is hard to detect on Earth.
Different parts of the spectrum provide different information.
Stars emit mainly ultraviolet radiation.
65. What does the frequency of light mean?
The distance from one maximum to another.
How bright the light will be.
The distance it will travel in 1 second.
The number of times the wave cycle repeats every second.
66. The energy of a photon can be expressed by
E=hf.
E=hc.
E=cλ.
E=f/λ.
67. What is the purpose of the objective lens in a refracting telescope?
To focus the incoming light.
To change the speed of the incoming light.
To interfere the incoming light.
To diffract the incoming light.
68. If a refracting telescope has an objective lens with a focal length of 300cm and has an eyepiece with a focal length of 3cm, the magnification is?
M = 100.
M = 1/100.
M = 300.
M = 3/300.
69. Active optics is used in modern telescopes to
change the focal length of the primary mirror for different astronomical objects.
change the detector sensitivity for measuring different wavelengths.
maximise the light gathering power of the telescope.
change the shape of the primary mirror to correct for atmospheric disturbances.
70. The Earth’s atmosphere is responsible for which three phenomena in observational astronomy?
Atmospheric diffraction, Chromatic aberration, and Atmospheric scattering.
Atmospheric refraction, Atmospheric scattering, and Atmospheric absorption.
Atmospheric scattering, Spherical aberration, and Atmospheric refraction.
Wave particle duality, Atmospheric scattering, and Atmospheric absorption.
71. For what reason is interferometry used when using multiple telescopes to observe astronomical objects?
To increase the resolving power of the detector.
To remove the effect of light pollution.
To measure different frequencies of light simultaneously.
To reduce the magnification.
72. Gravitational wave detectors aim to measure the radiation emitted by accelerating masses by
using the James Webb Space Telescope.
using long-baseline laser interferometers.
using multiple radio telescopes around the world.
detecting Cherenkov radiation with photomultiplier tubes.
73. Which of the following statements is false?
Red light has a longer wavelength than blue light.
Light travels faster in glass than in a vacuum.
Light is both a wave and a particle.
Light is a wave of varying electric and magnetic fields.
74. A Schmidt-Cassegrain telescope uses which of the following components?
Both lenses and mirrors.
Only mirrors.
A diffraction grating.
Only lenses.
75. If a telescope has an objective with a focal length of 90 cm and an eyepiece with focal length of 3 cm, what is the magnification of the telescope?
270
30
1/30
60
76. What are the three important qualities of a telescope?
Magnification, Light Gathering Power, Resolving Power.
Magnification, Diffractive Power, Light Gathering Power.
Diffractive Power, Light Gathering Power, Resolving Power.
Magnification, Diffractive Power, Resolving Power.
77. What causes the twinkling of stars?
Atmospheric refraction.
Atmospheric Dispersion.
The variation in intensity of light emitted by the star.
Impurities in the lens of the telescope or eye.
78. On a cloudless day, why does the sky look blue?
Because the sky reflects the blue colour of the sea.
Because blue light is scattered more than red light.
Because red light is scattered more than blue light.
Because the red light is absorbed by the atmosphere.
79. Grazing incidence mirrors are used to focus light in what type of telescope?
Radio telescopes.
Infra-red telescopes.
X-Ray telescopes.
Optical telescopes.
80. By what method are radio telescopes able to obtain high-resolution images?
By having a large field of view.
By using the interference of signals from many radio telescopes.
By using laser guide adaptive optics.
By using computer grinding to construct very smooth mirrors.
81. Super-Kamiokande is an experiment designed to detect what?
Neutrinos.
Earth-like planets.
Gravitational waves.
Gamma rays.
82. The James Webb telescope is intended to replace what?
The Chandra observatory.
The Infra Red Astronomical Satellite.
The Compton Gamma Ray observatory.
The Hubble Space telescope.
83. Which of the following is a true statement?
Light is both a wave and a particle.
Light is neither a wave nor a particle.
Light is a particle, but not a wave.
Light is a wave, but not a particle.
84. Which of the following describes waves whose wavelength is approximately 1 mm?
Visible red light.
Microwaves.
Radio waves.
X-Rays.
85. What is the phenomenon where the velocity of light in a medium depends on its wavelength?
Interference
Dispersion
Diffraction
Refraction
86. Newton's telescope was a
refracting telescope.
Cassegrain telescope.
reflecting telescope.
prime focus telescope.
87. Modern telescopes use CCDs to capture the light. What does the acronym CCD stand for?
Count Collecting Device.
Charge Coupled Diode.
Charge Collecting Diode.
Charge Coupled Device.
88. Ultra-Violet (UV) radiation is emitted by objects of temperature around
500 K
1 000 000 K
10 K
10,000 K
89. The Chandra Observatory is an observatory for
X-Ray astronomy.
Radio astronomy.
Neutrino astronomy.
Infra-red astronomy.
90. Why can X-Rays penetrate inside solids?
They are of very small frequency.
They are very non-reactive.
They have very small wavelengths.
They are out of phase with ordinary matter.
91. Why are neutrinos so hard to detect in astronomical observatories?
The neutrinos decay before reaching the Earth.
The neutrinos interact only weakly.
Neutrinos are absorbed in the upper atmosphere.
There are no astronomical sources of neutrinos.
92. Which of the following is NOT a good source of gravitational waves?
Pulsars.
Magellanic clouds.
Supernova explosions.
Black Hole binary systems.
93. A reflective diffraction grating is separating the light colours and creates a spectrum. What happens if the incoming light is changed from blue to red?
Nothing. Diffraction is wavelength-independent.
The outcoming light stays blue.
The red light is transmitted through the grating because only blue light is scattered.
The angle between the diffraction orders becomes larger.
94. Which statement is wrong?
The energy of photons is just dependent on the frequency.
Light has a constant speed in vacuum.
Light travels with different speeds depending on the material.
Light travels always with a constant speed.
95. Why are most of the modern telescopes for visible light reflecting telescopes?
Lenses cannot be used for visible light.
It is not possible to melt enough glass to fabricate a large lens.
Mirrors are easier to make and to mount.
They have no aberration.
96. Why are astronomers interested in different parts of the spectrum?
The results would otherwise interfere destructively.
The different colours are nice.
Different parts of the spectrum contain different information.
At some locations at the sky certain detectors do not work.
97. A Cassegrain telescope may have a focal length of 100 cm. The diameter of the mirror shall be 25 cm. The eyepiece used in this configuration has a focal length of 1 cm and a diameter of 0.5 cm. What magnification is achieved?
A magnification of 25.
It is not possible to calculate the magnification with these parameters.
A magnification of 50.
A magnification of 100.
98. Why is the colour of the sun during sunset red?
The diffraction of light is different. Blue light is more strongly diffracted.
The sun changes its colour in 24 h from blue to red and back to blue.
The refraction of light is different. Blue light is more strongly refracted.
The scattering of blue light is stronger than red light.
99. What is true for an IR detector used in astronomy?
They are not used. The IR part of the spectrum does not contain any information.
Light is absorbed and the temperature increase is measured. Therefore, it is good to cool them.
The electrons in the detector need to get some additional energy to be used for detection. Thus, these detectors need to be heated.
They are based on the photoelectric effect: light kicks out electrons from the material.
100. What is the reason why X-ray telescopes are so much different from telescopes for the visible part of the spectrum?
Materials are nearly transparent in the X-ray band. Standard optical configurations cannot be used.
It is too dangerous to observe X-rays from astronomical objects.
It is hard to find materials that can be used under X-ray irradiation.
Materials used in these telescopes change the colour of the light. It is complicated to compensate this effect.
101. What can be observed with radio astronomy?
The moon.
Radio broadcast of other civilizations in the universe.
Wavelengths that are in the region of cm.
Wavelengths that are shorter than the visible light.
102. Gravitational wave astronomy is called a new window to the universe. Why?
They need to be observed from space.
Gravitational waves can be observed with a simple refractive telescope. Therefore, it would be easier to observe astronomical objects.
Gravitational waves have only a weak interaction with matter. They are carrying information from objects that cannot be observed by studying their emitted electromagnetic radiation.
Gravitational waves will allow a very high resolution when combining a gravitational wave telescope with a CCD.
103. Adaptive optics is a technique that reduces the effect of atmospheric turbulence by
evacuating the telescope tube.
adjusting the eyepiece position
varying the mirror reflectivity.
bending the telescope mirror.
104. The angular size of the Moon is
50 degrees.
5 degrees.
0.1 degree
0.5 degree.
105. Which of the following uses a grazing incidence telescope?
International Ultraviolet Explorer.
Spitzer.
Hubble Space telescope.
Chandra.
106. Modern observatories mostly use
observatories at low altitude.
photographic film.
CCD detectors.
refractive objectives.
107. LIGO is an acronym for:
Light Ingoing Ground Observations.
Light Incident Gravitational Observation.
Laser Interferometric Gravitational-wave Observatory.
Laser Incoming Ground Observation.
108. If the diameter of the objective of a telescope is doubled, what happens to its light gathering power? The light gathering power
is increased by a factor of three.
is increased by a factor of four.
is increased by a factor of two.
remains the same.
109. Which of the following processes is responsible for the absorption of Infra-Red radiation?
Splitting of the atomic nuclei.
Breaking of the chemical bonds.
Infra-Red radiation is not absorbed.
Excitation of vibrational modes of molecules.
110. Long Baseline Interferometry is a technique often used in radio astronomy to
improve the resolution of objects.
remove the effect of Cerenkov radiation.
reduce the effect of light pollution in urban skies.
image neutrinos.
111. An electromagnetic wave having a wavelength of 550 nm is:
visible radiation.
ultra-violet radiation.
gamma radiation.
infrared radiation.
112. In a diffraction grating the angle between the zero order (white fringe) and first order (coloured fringe) depends on the
intensity of the light.
wavelength of the light.
brightness of the light.
speed of the light.
113. A Cassegrain telescope
has a short focal length.
is not a widely used optical design.
is a common optical design used at modern observatories.
has a wide field of view.
114. Infra red detectors can work by measuring
energetic charged particles.
Cerenkov radiation.
the temperature rise in a material.
radioactive particles.
115. Wave particle-duality relates to
visible radiation.
UV radiation.
all of the above.
infra-red radiation.
116. The International Ultraviolet Explorer (IUE) experiment
is not a space mission.
is currently being built.
is currently in orbit.
has since finished operation.
117. Scintillation detectors can be made from
water.
stainless steel.
wood.
aluminium.
118. The typical wavelength of an X-ray photon is
50 nm.
1.5 µm.
0.1 nm.
600 nm.
119. A light wave with large amplitude has a
long wavelength.
low brightness.
high frequency.
high brightness.
120. Radio telescopes
operate only at night.
require a very smooth surface.
do not require a very smooth surface.
need to be cooled.
121. The ISO satellite is sensitive to
UV.
Gamma rays.
IR.
X-rays.
122. A Newtonian telescope utilises a
lens.
flat secondary mirror.
curved secondary mirror.
corrector plate.
123. A prime focus telescope represents a feasible optical configuration
when interference is used.
when the diameter of the prime mirror is very large.
when the focal length is very long.
for amateur telescopes.
124. Which of the following parameters is the same for all electromagnetic waves propagating in a vacuum?
Amplitude
Colour
Wavelength
Speed
125. Which of the following statements correctly describes the wavelength of an electromagnetic wave?
The wavelength is the distance travelled by the wave in a short time.
The wavelength is the distance between two consecutive peaks.
The wavelength is the distance travelled by the wave in 1 second.
The wavelength is the distance between a trough and a peak.
126. Interference between the light coming from different telescopes is used to
improve the resolution.
improve the magnification.
improve the light gathering.
improve the light spectrum.
127. Why does a light ray bend when it crosses the boundary between two different media at an oblique angle?
Because the amplitude is reduced.
Because it interferes with the surface.
Because the frequency increases.
Because the speed of light changes.
128. A Newtonian telescope has
a correction plate
a flat secondary mirror
a diverging secondary mirror
just the primary mirror
129. With respect to a dim light, a bright light emits
photons with shorter wavelength.
photons with higher amplitude.
more photons.
photons with longer wavelength.
130. The Hubble telescope was placed in space in order
to not be limited by the Earth’s horizon.
to improve the magnification.
to not be limited by the Earth’s atmosphere.
to be close to the stars.
131. An electromagnetic wave with a wavelength of 100 nm is
IR radiation.
visible radiation.
UV radiation.
microwave radiation.
132. The angular size of the Moon is
1.8 degrees
18 degrees
1 800 arcminutes
1 800 arcseconds
133. Hello
World
Submit Quiz