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