Exploring the Cosmos - Class Test 1 - Complete B
1. How did Johan Bayer name the stars in the sky? He named them
in terms of their relative brightness within constellations.
based on their colour.
in terms of their co-ordinates in the sky.
in the order he found them.
2. If a star's annular parallax is 0.4, what is the distance?
2.5 pc
2.5 Mpc
2.5 AU
2.5 LY
3. The surface temperature of our Sun is roughly
30,000 K
6,000 K
3,000 K
60,000 K
4. Two isotopes of the same chemical have the same number of what in their nuclei?
electrons
protons
neutrons
photons
5. Which of the following types of stars are most abundant in the universe?
Red giants
Red dwarfs
White dwarfs
Blue giants
6. At roughly what distance is the nearest star to our own?
4.3 parsecs
43 lightyears
43 parsecs
4.3 lightyears
7. Which process allows for the building up of elements heavier than iron?
Helium capture.
Photodisintegration.
The alpha-process.
Neutron capture.
8. What is the name given to the process by which elements are formed in stars?
Stellar photosynthesis
Stellar construction
Stellar nucleosynthesis
Stellar manipulation
9. Which of the following regions of our Sun is the hottest?
Corona
Chromosphere
Convection zone
Photosphere
10. What temperature range do Main Sequence stars fall into?
30 K to 300 K
30,000 K to 300,000 K
3,000 K to 30,000 K
300 K to 3,000 K
11. Roughly how many stars are there in our own galaxy?
100 million
100 billion
1 billion
1 million
12. A hydrogen nucleus contains how many protons?
4
2
1
3
13. Which of the following parameters is the same for all electromagnetic waves propagating in a vacuum?
Amplitude
Wavelength
Colour
Speed
14. 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.
15. A spectrograph orders electromagnetic waves with respect to which of the following?
Their wavelength.
Their source.
Their amplitude.
The number of photons in the waves.
16. Diffraction gratings are used to
detect infrared radiation.
increase the resolution of telescopes.
reduce diffraction of telescopes.
break up light into a spectrum.
17. The focal length of an ideal mirror depends on the
thickness of the mirror.
colour of the incident light.
diameter of the mirror.
curvature of the mirror.
18. 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 increased by a factor of two.
The light gathering power is decreased by a factor of four.
The light gathering power remains the same.
19. How old is the universe?
About 14 billion years.
About 50 billion years.
About 6 thousand years.
The universe is infinitely old.
20. The sky is dark at night because
there is dark matter in between the stars.
our eyes are not sensitive enough.
the universe is so young that light from faraway stars has not yet reached us.
the universe is only sparsely populated with stars.
21. What is the observable universe?
The portion of the universe that our eyes can see.
Parts of the universe that the most powerful telescopes can resolve.
All parts of the universe that are not obscured by celestial objects.
The portion of the universe from which light had enough time to travel to us.
22. Ptolemy believed that
Newton was the greatest scientist of all time.
all the stars were on a celestial sphere.
everything must move along one simple perfect circle.
some of the planets orbit around the Sun.
23. Einstein's special theory of relativity implies that
nothing can travel faster than the speed of light.
nothing is relative.
everything is relative.
all motion is relative to the centre of the universe.
24. Kepler's Laws show that
planetary orbits are elliptical.
a planet orbits the sun with constant speed.
there is no special centre around which the universe rotates.
planets cannot be more massive than the star around which they orbit.
25. Globular clusters are usually found in the
discs of galaxies and contain population II stars.
halos of galaxies and contain population II stars.
halos of galaxies and contain population I stars.
discs of galaxies and contain population I stars.
26. Our Sun is situated in
a globular cluster in the galactic disc about half of its radius from the centre.
the disc of the galaxy close to the edge of the disc.
a globular cluster in the halo of the galaxy.
the disc of the galaxy about two thirds of its radius from the centre.
27. Neutral hydrogen can be detected by astronomers because it
glows with a bright blue colour.
forms dark clouds in the disc of a spiral galaxy.
radiates a sharp 21 cm radio signal.
reflects blue light from nearby stars.
28. The approximate position of the centre of the Milky Way galaxy was first found, using optical telescopes, by
looking for the central bulge.
observing stars moving round the massive black hole in the centre.
measuring the position of visible open star clusters.
measuring the position of visible globular clusters.
29. The diameter of the Milky Way Galaxy is about
25 to 30 kpc.
25 to 30 Mpc.
250 to 300 pc.
25 to 30 pc.
30. Of the stars in a spiral galaxy,
all the stars in the disk move with the same angular velocity, like a rigid turntable.
those in the outer reaches of the disk are slowly spiralling inwards due the presence of dark matter in the galaxy.
those in the disc component move in nearly circular orbits in the plane of the disc and around the galactic centre.
those in the spherical component move in circular orbits with random orientations around the galactic centre.
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