Astronomy at the Vrije Universiteit Brussel


TEST YOUR ASTRONOMICAL KNOWLEDGE

Convention:
1,78 means: one plus 78/100
100.000 means: one hundred thousend

Example:
1 Astronomical unit (1 AU) = 150.000.000 km

1. The best way to determine the distance to a star, is by observing its position with a time interval of:

a.  1 hour
b.  6 hours
c. 12 hours
d.  6 months
e. 12 months
2. The semi major axis of the orbit of Neptune around the Sun is 30,06 times longer than that of the Earth. Calculate the orbital period of Neptune around the Sun?

a.   30,06 years
b.   75,15 years
c.  164,8 years
d.  903,6 years
e. 1375 years
3. What is the frequency of a photon traveling at light velocity and having a wavelength of 100 metre?

a.       100 Hz
b.     3.000 Hz
c.    30.000 Hz
d. 3.000.000 Hz
e. 3 x 109 Hz
4. How does an observer on Earth see the spectral lines in absorbtion and emission of an object that moves away from the Earth at a large speed?

a. They remain unchanged
b. Their intensity increases
c. Their intensity decreases
d. They are shifted towards the blue end of the spectrum
e. They are shifted towards the red end of the spectrum
5. How long does it take for the sunlight to arrive at Pluto (at 40 AU)?

a.  13 seconds
b.   2,5 minutes
c.   1,3 hours
d.   5,6 hours
e. 233 hours
6. The solar system comtains 1 sun, 8 planets, with more than 100 moons, many thousends of planetoïds, millions of comets and billions of asteroïds. How many % of the mass of the solar system is contained in the Sun (accuracy within 1%)?

a.  10 %
b.  50 %
c.  90 %
d.  96 %
e. 100 %
7. Why is the sky blue on a bricht and cloudless day?

a. The air absorbs every colour emitted by the Sun, exept the blue
b. The molecules of the atmosphere of the Earth get a blue colour when they interact with sunlight
c. The air reflects the blue colour of the oceans
d. O2 and N2 molecules scatter sunlight preferentially in the blue
e. Dust particles in the air are blue and reflect only the blue colour of sunlight
8. The gravitational acceleration on the surface of the Earth is 9,81 m/s2. Jupiter contains 318 times more mass and has a 11,2 times larger radius as the Earth. The gravitational acceleration on the surface of Jupiter is:

a.   0,875 m/s2
b.   9,81 m/s2
c.  24,87 m/s2
d.  28,39 m/s2
e. 278,25 m/s2
9. A plausible theory for the formation of the solar system needs not to explane one of the following statements:

a. The orbits of all the planets are almost in the same plane
b. The moon rotates around the Earth and spins around its own axis in such a way that it always shows the same side to the observer on Earth
c. Most moons spin around their axis of rotation in the same sense as the rotation of the planets around the Sun
d. Planets rotate around the Sun in the same sense (counter-clockwise) as the sense of rotation of the Sun around its own axis
e. Long periodical comets (from Oort's cloud) need not to orbit in the ecliptica
10. The Sun radiates at a rate of 4 × 1026 watt; how much mass (per second) is hereby converted into energy?

a.       0,5 kg/s
b. 153.000 kg/s
c. 314.526 kg/s
d. 4,44 billion kg/s
e. 8 × 1011 kg/s
11. Rigel is a star 44.000 times brighter than the Sun and has an effective temperature of 20.000 K. What is the radius of Rigel (Teff,o=5770 K)* ?

a.     0,29 Ro which makes Rigel a "White Dwarf"
b.     3,5 Ro which makes Rigel a "Main Sequence star"
c.     4,3 Ro which makes Rigel almost a "Giant"
d.    17,1 Ro which makes Rigel a "Giant"
e. 2.200 Ro which makes Rigel a "Supergiant"
* Subscript o = Sun

12. Why do clusters provide an excellent test for stellar evolution?

a. All stars in a cluster have approximately the same age
b. Stars in a cluster all have approximately the same mass
c. Clusters contain always approximately the same number of stars so that they can easily be compared to one another
d. Clusters contain almost the same distribution of stars with different ages
e. Clusters contain stars that are at the end of their evolution
13. The Sun is located at 8,2 kpc from the centre of the Milky Way and rotates once in 200 million years around this centre. What is the rotational velocity of the Sun in the Milky Way (1pc = 3,26 light years)?

a.     1,7 km/s
b.    20 km/s
c.    35 km/s
d.   250 km/s
e. 1.000 km/s


Updated: Thu 01 Jan 1970 01:00:00