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