Download Conceptual Physics

Science Olympiad Scrimmage - 2011
Name:
Date:
Topic: Astronomy
Directions: Perform all tasks as requested for full credit. Each task is worth 1 point.
1. On the diagram below, perform each of the following tasks: Note: you may use the margins if
necessary.
a. Place an appropriate label on the x-axis (Note that there are two possible designations).
b. Place an appropriate label on the y-axis (Note that there are two possible designations).
c. Show where giant stars are located by writing “GIANT” on the diagram.
d. Show where supergiant stars are located by writing “SUPERGIANT” on the diagram.
e. Show where white dwarfs are located by writing “WHITE DWARFS” on the diagram.
f. Show where the main-sequence is by writing “MAIN-SEQUENCE” on the diagram.
g. Place an arrow on the diagram to show increasing mass on the main-sequence. Label
this arrow with “INCREASING MASS.”
h. Place an arrow on the diagram to show increasing temperature. Label this arrow with
“INCREASING TEMPERATURE.”
i. Show where blue stars are located by writing “BLUE STARS” on the diagram.
j. Show where red stars are located by writing “RED STARS” on the diagram.
-10
-8
-6
-4
-2
0
2
4
6
8
10
12
14
16
18
Science Olympiad Practice Exam
Multiple Choice: Answer each question with the choice that fits best. Each question worth 1 point.
2. Stars spend about 90% of their life:
a. As protostars
b. On the main sequence
c. As red giants
d. As planetary nebula
e. Forming planets.
3. In a random sample of stars in the Sun’s neighborhood, you would expect about 90%
of them:
a. To be red giants
b. To be white dwarfs
c. To be main sequence stars
d. To have just been born
e. To be older than the Sun
4. A star near the top of the main sequence has a mass about:
a. Twice the Sun’s mass
b. Five times the Sun’s mass
c. 60 times the Sun’s mass
d. 10,000 times the Sun’s mass
5. A star near the top of the main sequence has a luminosity about:
a. Twice the Sun’s luminosity
b. Five times the Sun’s luminosity
c. 20 to 30 times the Sun’s luminosity
d. 10,000 times the Sun’s luminosity
6. How would you expect the lifetime of a massive star near the top of the main sequence to compare to
the Sun’s?
a. Longer
b. About the same
c. Shorter
d. Very, very much shorter
7. What do the colors of stars in the H-R Diagram tell us?
a. The size of the star.
b. The luminosity of the star.
c. The surface temperature of the star.
d. The core temperature of the star.
e. The mass of the star.
8.
Stars along the main sequence burn
for the majority of their lives.
9.
When stars move off the main sequence, they begin fusing
10. Name two characteristics of high mass stars that are on the main sequence:
11. List the spectral type of stars in order from high temperature to low temperature.
2
.
Science Olympiad Practice Exam
12. The diagram below shows the life track of a 1-solar mass star from birth onto the main-sequence to
death. Identify each stage along its path along with the burning process correctly to get full credit.
Each response worth 1 point.
e.
c.
f.
d.
b.
a.
g.
Extra Credit(1 point each):
13. What is the composition of a white dwarf star?
14. What is the composition of a neutron star?
3
Science Olympiad Practice Exam
15. Star A has an apparent magnitude of 3 and Star B has an apparent magnitude of 5. Which star is
brighter in our sky?
a.
b.
c.
d.
Star A
Star B
The two stars have the same brightness in our sky, but Star A is closer to us than Star B.
There is not enough information to answer the question.
16. What do we mean by the interstellar medium?
a.
b.
c.
d.
The dust that fills the halo of the Milky Way Galaxy.
The name of an oracle who can channel messages from beings that live near the star called Vega.
The middle section of the Milky Way Galaxy.
The gas and dust that lies in between the stars in the Milky Way Galaxy.
17. Approximately what core temperature is required before hydrogen fusion can begin in a star?
a. 10,000 K
b. 10 trillion K
18. The ultimate fate of our Sun is to
a.
b.
c.
d.
c. 10 billion K
d. 10 million K
.
become a rapidly spinning neutron star
become a white dwarf that will slowly cool with time
explode in a supernova
become a black hole
19. After a supernova explosion, the remains of the stellar core
a.
b.
c.
d.
e. 1 billion K
.
be either a neutron star or a black hole
will always be a black hole
will always be a neutron star
may be either a white dwarf, neutron star, or black hole
20. How are low-mass red giant stars important to our existence?
a.
b.
c.
d.
These stars provide most of the light that reaches us from globular clusters.
These stars manufactured most of the carbon atoms in our bodies.
These stars manufactured virtually all the elements out of which we and our planet are made.
These stars generate the energy that makes life on Earth possible.
21. Suppose that a white dwarf is gaining mass through accretion in a binary system. What happens if the
mass someday reaches the 1.4 solar mass limit?
a. The white dwarf will collapse to become a black hole.
b. The white dwarf will collapse in size, becoming a neutron star.
c. The white dwarf will undergo a nova explosion.
d. The white dwarf will explode completely as a white dwarf supernova.
22. A typical white dwarf is
.
a. as massive as the Sun but only about as large in size as Jupiter
b. as massive as the Sun but only about as large in size as Earth
c. as large in diameter as the Sun but only about as massive as Earth
d. about the same size and mass as the Sun but much hotter
23. What is the basic definition of a black hole?
a. a compact mass that emits no visible light
b. a dead star that has faded from view
c. an object with gravity so strong that not even light can escape
d. any object made from dark matter
24. What do we mean by the event horizon of a black hole?
a. It is the very center of the black hole.
b. It is the place where X rays are emitted from black holes.
c. It is the distance from the black hole at which stable orbits are possible.
d. It is the point beyond which neither light nor anything else can escape.
4
Science Olympiad Practice Exam
25. What do we mean by the singularity of a black hole?
a. It is the "point of no return" of the black hole; anything closer than this point will not be able to
escape the gravitational force of the black hole.
b. The term is intended to emphasize the fact that an object can become a black hole only once, and
a black hole cannot evolve into anything else.
c. It is the edge of the black hole, where one could leave the observable universe.
d. It is the center of the black hole, a place of infinite density where the known laws of physics cannot
describe the conditions.
26. Pulsars are thought to be
a. unstable high-mass stars
b. rapidly rotating neutron stars
.
c. accreting black holes
d. accreting white dwarfs
27. According to the inverse square law of light, how will the apparent brightness of an object change if its
distance to us triples?
28. What is the difference between apparent magnitude and absolute magnitude?
29. 1 parsec is equivalent to
light years.
30. In the space below, determine the distance to Alpha Centauri given a measured angle of parallax of
0.742 arcsecond.
31. The variable double star T Tauri has an apparent magnitude of 9.81 and an absolute magnitude of
3.57. Determine the distance of this star in the space below. (Note: you must calculate.)
32. In the space below, determine the Luminosity of our Sun if the apparent brightness is 1300 W/m 2. You
must show your work for this calculation.
33. Use the Sky Chart on the next page to assist you in performing each of the following tasks:
a. Identify the location of the Rosetta Nebula on the chart
b. Identify the location of the T Tauri on the chart.
c. Identify the location of NGC 2440 on the chart.
5
34. For each of the images on the pages that follow, identify what the image is and its name as appropriate.
A.
B.
C.
D.
E.
F.
G.
H.
I.
J.
K.
L.
Science Olympiad Practice Exam
A.
B.
C.
D.
E.
F.
8
Science Olympiad Practice Exam
G.
H.
I.
J.
K.
L.
9
Science Olympiad Practice Exam
Key:
-10
-8
-6
-4
-2
0
2
4
6
8
10
12
14
16
18
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
21.
22.
b
c
c
d
d
c
hydrogen
helium
larger radius, more luminous, short life, blue
OBAFGKM
a. Main Sequence, H Fusion
b. Subgiant – H Shell Burning
c. Helium Flash
d. Subgiant – He core burning
e. Red Giant – Double Shell Burning – H, He
f. Planetary Nebula
g. White Dwarf
c
neutrons
a
d
d
b
a
b
c
b
10
Science Olympiad Practice Exam
23.
24.
25.
26.
27.
28.
29.
30.
31.
32.
33.
c
d
d
b
If the distance tripled, the apparent brightness would diminish by a factor of 1/3 2 or 1/9.
Apparent magnitude is the brightness of the star in the sky as seen relative to other stars
while absolute magnitude is the apparent brightness if the star was placed 10 parsecs from
Earth.
3.26 ly.
d = 1/p = 1/.742 = 1.35pc.
177 ly
Luminosity = 4d2 x apparent brightness = (4(1.51011m)2)(1,300 W/m2) = 3.681026 W
A.
B.
C.
D.
E.
F.
G.
H.
I.
J.
K.
L.
Mira
SNR 0509-67.5
Carina Nebula
CH Cyg
SNR 0509-67.5 (X-ray)
NGC 2440
Kepler’s SNR
Sirius B (X-ray)
Tycho’s SNR
T Tauri
Rosette Nebula
Globular cluster – M15
11