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