NAME _____________________________ ID # ___________ LAB # _____________

Astronomy 1001

Midsemester Exam #2 - Section 1

Read Instructions Carefully:

The essay questions of this exam are graded by more than one person, so it is imperative that your NAME BE LEGIBLY WRITTEN ON EACH PAGE OF THE ESSAY PORTION!

1. MARK THE ANSWERS YOU CHOOSE ON THIS TEST AS IT IS YOUR ONLY

OPPORTUNITY TO CHECK WHICH ANSWERS YOU GOT RIGHT OR

WRONG. This will not be done for you at a later time in the departmental office.

Exams will be returned to the alphabetical boxes in the North wall of the Physics

building approximately 3-4 days after the exam.

2. Print your NAME, ID # and SECTION # on your computer answer sheet where

appropriate. Your SECTION # should read 01. All three items are necessary for the

proper scoring and computer transfer of your scores.

3. Use a pencil, make your marks dark and neat, and erase thoroughly.

4. There is only one answer to each question. Choose the best answer.

5. You may use this test for scratch paper.

6. One page (two sides) of notes is allowed for the exam.

I. Multiple Choice (3 pts. each)

1. Comets are

a) bright displays in Earth's atmosphere due to solar radiation

b) segments of the zodiacal light

c) luminous trails of fast-moving meteors

d) conglomerations of ices, rocky particles and gases

e) disturbances in the solar wind

2. The atmospheres of Jupiter and Saturn are composed mostly of

a) methane

b) carbon dioxide

c) hydrogen

d) ammonia

e) a mixture of methane and ammonia

3. A cool gas in front of a hotter source produces

a) absorption lines in its spectrum

b) a continuous spectrum

c) X-rays

d) a spectrum of emission lines

e) protons

4. Jupiter has a strong magnetic field because

a) it has a magnetized iron core

b) currents are generated in its upper atmosphere

c) it is rotating fast and has a conductive inner region

d) its large inner moons generate the field

e) it captures parts of the Sun's magnetic field

5. To produce an absorption line, electrons in atoms must

a) go up in energy level

b) drop down in energy level

c) stay in the same energy level

d) escape the atom completely

e) jump between atoms

6. A heated electrical filament produces

a) an emission-line spectrum

b) an electrostatic spectrum

c) absorption lines

d) a continuous spectrum

e) a type G spectrum

7. Mars has an atmosphere and Mercury does not, even though they have similar surface gravities. What is the main reason for the difference?

a) the two planets had different compositions when they were formed

b) Mars has a slower orbital velocity than Mercury

c) Mercury's rotates slower than Mars

d) the solar wind is weaker around Mars

e) Mercury has a higher surface temperature

8. The tail of a comet always points

a) forward along the comet's orbit

b) backward along the comet's orbit

c) away from the Sun

d) toward the ecliptic

e) at right angles to the ecliptic

9. The existence of the Oort cloud was proposed to explain the

a) locations of the asteroids

b) source and orbits of comets

c) possibility of extraterrestrial life

d) origin of planets

e) orientation of the ecliptic

10. In what crucial way is the atmosphere of Earth very different from those of both Venus and Mars?

a) Carbon dioxide content. This gas is the dominant component on Venus and Mars, but is less than a few percent of Earth's atmosphere

b) Temperature near the surface. Earth's temperature is relatively cool, unlike those other two planets

c) Hydrogen content. This gas makes up a large fraction of the atmospheres of the other two planets

d) Methane content. This gas is present in larger quantities on Venus and Mars

e) Seasons. Venus and Mars do not have perceptible seasonal changes in climate

11. The usual period of the sunspot cycle is

a) 6 months b) 1 year c) 5 years d) 11 years e) 24 years

12. Evidence that convection dominates the heat flow in the outer layers of the Sun is provided by

a) the high temperature of the corona

b) heliocentric parallax

c) granulation in the photosphere

d) the temperature gradient from center to surface

e) the sunspot cycle

13. The greenhouse effect keeps the earth warmer because

a) most of the radiation from the sun is infrared

b) most of the radiation from the sun is yellow

c) the ozone layer absorbs ultraviolet

d) the ozone layer absorbs infrared

e) most of the radiation from the earth is infrared

14. The condition which would most likely give rise to a large albedo (high reflectivity) for a planet or moon is

a) no atmosphere

b) a thin atmosphere and many craters on the surface

c) a cloud-covered surface

d) a rotation axis inclined toward the Sun

e) an orbit which carries the planet close to the Sun

15. In the region of space between Mars and Jupiter we find the

a) orbits of many comets

b) planet Saturn

c) asteroid belt

d) vernal equinox

e) aphelion of the orbit of Halley's Comet

16. The physical structure of Saturn's rings is

a) a sequence of hundreds of separate rings made of ice and rock particles

b) a thin but extensive gas cloud over the equator

c) hot, excited plasma from the planet's magnetosphere

d) a thin solid ring, structured from ice and rock

e) a set of magnetic belts analogous to Earth's radiation belts

17. The debris left behind by a comet in its orbit is thought to cause

a) meteor showers

b) asteroids

c) minor planets

d) precession

e) the formation of new comets

18. Why was the discovery of Charon valuable to planetary scientists?

a) It confirmed Bode's law

b) It confirmed Newton's laws

c) It indicated the mass of Pluto

d) It was the first moon known to have an atmosphere

e) It was the first asteroid whose composition could be determined

19. The corona of the sun has a temperature of over one million degrees, much hotter than the solar atmosphere. Yet the corona is quite difficult to see. Why?

a) the energy in the corona flows down to the photosphere

b) it is too hot to produce visible light (produces only X-rays)

c) the coronal gas is very thin and low in density

d) we see through the photosphere into the very much hotter core of the sun

e) prominences block our view of the corona

20. Earth's atmosphere and oceans came mostly from

a) a single, giant comet striking Earth

b) volcanic and gaseous emission from the interior

c) melting of the ice caps

d) the original gaseous envelope that surrounded Earth after it formed

e) cosmic rays from the Sun

21. The colors in Jupiter's atmosphere

a) are due to chemical processes in the atmosphere

b) are emissions from hot gases of different temperatures

c) are due to biological processes in the atmosphere

d) are not real; pictures of Jupiter are computer color enhanced

e) indicate its surface temperature

22. The rings of Saturn may have been formed when

a) Saturn passed through the asteroid belt, collecting many small moons

b) material was pulled out of Saturn by one of its moons

c) a satellite of Saturn was torn apart by tidal forces

d) Jupiter passed very close to Saturn and disrupted one of its moons

e) none of a-d

23. The two most common constituents in meteorites are

a) methane and ammonia

b) hydrogen and helium

c) rock and iron

d) carbon

e) similar to comets

24. A spectrum of emission lines is produced by

a) a hot thin gas

b) liquid droplets

c) an opaque surface at high temperature

d) electric currents

e) magnetized atoms

25. Sunspots appear to be darker than their surroundings because

a) they are regions of lower temperatures

b) of obscuring clouds in the solar atmosphere

c) they contain no magnetic fields

d) of interplanetary dust and gas

e) they are holes in the corona with no light coming from them

NAME _____________________________ ID # ___________ LAB # _____________

Astronomy 1001

Midsemester Exam #2 - Section 1

II. Essay (15 pts. each)

1. Discuss the existing evidence that a giant impact caused a major catastrophe for life on Earth about 65 million years ago.

2. How did we know that the rings of Saturn could not be solid structures even before viewing them closely enough to see that they are made of small particles in separate orbits?

NAME _____________________________ ID # ___________ LAB # _____________

Astronomy 1001

Midsemester Exam #2 - Section 1

3. Describe the changes in sunspot activity and magnetism that are associated with the 11 year solar cycle.

4. Why do we call meteorites and comet nuclei "Rosetta Stones" of the solar system, and what can we learn by studying them?