For astronomy and mathematics

1. Multiple choice exercises-3
1. Giventhat light travelsin a speedof 300,000 km/s and that it takes approximately2 s to travel
from the Earth to the Moonand back to the Earth, what is the distance betweenthe Moon
and the Earth? (Ignore any other force that may slowdown particlesof light.)
a. 300,000 km
b. 600,000 km
c. 150,000 km
2. Distances betweenobjectsinspace are very large.Instead of measuringdistance in milesor
kilometers,astronomersuse a measurementunitcalledan astronomical unit(AU).1 AU
equalsthe average distance from the Earth to the Sun. Sirius is the brighteststar in the night
sky. It is located at about 544,000 AU from the Earth. Whichstatementcorrectly compares
the apparent brightnessof Siriusand the Sun?
a. Siriuslooksbrighterthanthe Sunbecause itislocatedcloserto the Earth.
b. The Sun looksbrighterthanSiriusbecause itislocatedcloserto the Earth.
3. What is the value ofthe coefficient xof the equilibrium 𝑥 𝐻 → 𝐻 + 𝐻1
1
1
3
1
2
of the nuclear
fusion(the nuclear chemical reaction that takesplace inside the core of the stars)?
a. 1
b. 0
c. 2
d. 3
4. Whichplanetfrom the belowis closerto our planet?
a. Neptune
b. Jupiter
5. Whichplanetis closerto the Sun?
a. Venus
b. Uranus
c. Mercury

2. 6. How many natural satellitesdoes our planethave?
a. 4
b. 7
c. 3
d. 1
7. From Einstein’stheoryof Special Relativitywe know that E=mc^2 where Ε is the energytaken
from an object with mass m and c is a constant (speedoflight) equal to 300,000. From the above
equationwe can inferthat:
a. The energyis proportional tothe mass of the object.
b. The energyisinverselyproportionaltothe speedof light.
c. The energyisinverselyproportionaltothe massof the object.
d. None of the abovementioned.
8. How many billionyearsold is the Sun?
a. 5
b. 2
c. 9
d. 11
9. How is our solar systemformed?
a. From a small cloud.
b. Froma small cloudof dust.
c. From a large cloudof gas.
d. From a large cloudof gas and dust.