ASTR 100 UIUC Exam 1 master set

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The primary purpose of a telescope is to

(A) make distant objects appear nearby.

(B) collect a large amount of light and bring it into focus.

(C) separate light into its component wavelengths.

(D) magnify distant objects.

(E) measure the brightness of stars very accurately

b) collect a large amount of light and bring it into focus.

Describing a star as being in the constellation Taurus (the bull) tells a modern astronomer that the star is

(A) one of a set of bright stars that make up a particular "picture" in the sky.

(B) somewhere in a particular region of sky having definite boundaries.

(C) in a distant galaxy located in a particular direction from Earth.

(D) inside our solar system

(B) somewhere in a particular region of sky having definite boundaries.

When Earth catches up a slower-moving Mars and passes it in its orbits in the same way that a faster runner

overtakes a slower runner in an outside lane, Mars

(A) exhibits retrograde motion.

(B) slows down because it feels Earth's gravitational pull.

(C) moves into a more elliptical orbit.

(D) becomes dimmer as it passes through Earth's shadow.

(A) exhibits retrograde

Kepler's laws worked, where Copernicus' original heliocentric model failed, because Kepler described the orbits

as

(A) around the Sun, not the Earth.

(B) elliptical, not circular.

(C) complex, with many more epicycles to account for retrograde motions.

(D) much larger than Copernicus had envisioned.

B) elliptical, not circular

What is the angular resolution of a telescope?

(A) its ability to separate light into its component colors for analysis

(B) its ability to see very faint objects

(C) its ability to make distant objects appear much closer to us

(D) its ability to distinguish two adjacent objects close together in the sky

D) its ability to distinguish two adjacent objects close together in the sky

Approximately when does a full Moon rise?

(A) noon

(B) sunrise

(C) 3am

(D) sunset

(E) midnight

D) sunset

The _____ of an object is a measure of its inertia. On the other hand, _____ is a measure of the gravitational

force on an object.

(A) energy, force

(B) momentum, energy

(C) force, energy

(D) weight, mass

(E) mass, weight

E) mass, weight

On a certain night you see a star set in the west at 7:10 P.M. You go out the next day. When does it set?

(A) 7:02 P.M.

(B) 7:10 P.M.

(C) 7:06 P.M.

(D) 7:18 P.M.

(E) 7:08 P.M.

C) 7:06PM

What problem does adaptive optics correct?

(A) the light pollution of urban areas

(B) defects in the optics of the telescope

(C) the opacity of the Earth's atmosphere to some wavelengths of light

(D) turbulence in the Earth's atmosphere that creates twinkling

D) turbulence in the Earth's atmosphere that creates twinkling

An arcsecond is a measure of

(A) time interval between successive orbital positions.

(B) time interval between oscillations of a standard clock.

(C) angle.

(D) speed.

C) angle

You see a waning gibbous moon high in the sky. What is the Moon's phase six hours later when it is near the

western horizon?

(A) waxing crescent

(B) waning gibbous

(C) new moon

(D) full moon

(E) third quarter

B) waning gibbous

Newton concluded that some force had to act on the moon because

(A) a force is needed to pull the moon away from straight-line motion.

(B) a force is needed to pull the moon outward.

(C) the moon moved at a constant velocity.

(D) a force is needed to keep the moon in motion.

A) a force is needed to pull the moon away from straight-line motion

Why do we see different phases of the Moon?

(A) The motion of the Moon in its orbit around Earth causes us to see different amounts of the sunlit side of the

Moon.

(B) The rotation of the Moon around its own axis causes us to see different amounts of the sunlit side of the

Moon.

(C) The motion of the Moon in its orbit around Earth causes us to see different amounts of Earth's shadow falling

on the Moon.

A) the motion of the Moon in its orbit around Earth causes us to see different amounts of the sunlit side of the Moon.

Each element has its own set of characteristic absorption lines because

(A) the temperature of each element can varies.

(B) elements can exist in different forms of matter.

(C) electron energy levels differ for each element.

(D) each element has a different mass.

(E) absorption lines depend upon the speed of the object.

C) electron energy levels differ for each element.

How would the Sun appear to move in the sky if you were at the north pole on June solstice (June 21)?

(A) It would appear to move parallel to the horizon at an elevation angle of about 23.5 degrees for a full 24 hours.

(B) It would appear halfway above the horizon and maintain this position for a full 24 hours.

(C) It would appear to rise in the east, reach an elevation angle of about 23.5 degrees at midday, and set in the

west 12 hours later.

(D) It would never reach above the horizon - it's 24 hours of darkness.

A) It would appear to move parallel to the horizon at an elevation angle of about 23.5 degrees for a full 24 hours.

Why is Jupiter never seen at midnight at Champaign-Urbana?

(A) Jupiter's orbit is inside Earth's and it is always within small angular separation from the Sun as seen on Earth.

(B) At midnight, Jupiter moves into Earth's shadow.

(C) Incorrect! Jupiter can be seen around midnight at Champaign-Urbana.

(D) At midnight, Jupiter is too far away from Earth to be seen by the naked eye.

C.) Incorrect! Jupiter can be seen around midnight at Champaign-Urbana

A Comet has an orbital period of 100 years. What is the average distance of the comet from the sun?

(A) 100 × (2/3) = 66.67 AU

(B) √1002

3

= 21.5 AU

(C) 50 AU

(D) √1003 = 1000 AU

(E) 100 × (3/2) = 150 AU

(B) √1002

At the equator,

(A) the day is longer than night on the equinoxes.

(B) the day is longer than night in the northern summer.

(C) the day is shorter than night on the equinoxes.

(D) day and night is of equal length throughout the year.

(E) the day is shorter than night in the northern summer.

D) day and night is of equal length throughout the year

Moon's shadow falling on the Earth is the reason we see

(A) Moon's shadow cannot fall on the Earth.

(B) lunar eclipses.

(C) solar eclipses.

(D) the phases of the Moon.

C) solar eclipses

If the Earth's spin axis were tilted by 50 degrees instead of 23.5 degrees,

(A) the difference in the seasons would be less noticeable than it is now.

(B) we would not be able to notice a difference between seasons.

(C) the difference in the seasons would be more noticeable than it is now.

(D) we would experience seasons nearly in the same way as we do now.

C) the difference in the seasons would be more noticeable than it is now.

Astronauts feel weightless in the Space Station because

(A) there is no gravity in space.

(B) the Space Station is traveling so fast.

(C) the Space Station is moving at constant velocity.

(D) the astronauts and Space Station are constantly in free-fall together around the Earth.

D) the astronauts and Space Station are constantly in free-fall together around the Earth

A total solar eclipse could never occur if the

(A) Moon were ten times its current size.

(B) Sun shrank to half its current size.

(C) Earth doubled its size.

(D) Moon were five times away from where it is now.

D) Moon were 5x away from where it is now.

Light is absorbed by atoms when electrons

(A) move from high energy levels to low energy levels.

(B) are absorbed by the nuclei.

(C) move from low energy levels to high energy levels.

(D) move in their orbit around the nucleus.

C) move from low energy levels to high energy levels.

Assuming clear skies everywhere, a total lunar eclipse is visible

(A) only to people in a circular area on Earth having a diameter equal to that of the Moon.

(B) to people anywhere in the night side of Earth.

(C) to everyone on Earth.

(D) only to people in a long narrow path much smaller than a hemisphere

B) to people anywhere in the night side of Earth.

Which has the largest light-gathering power?

(A) A telescope of 3 cm diameter and focal length of 75 cm.

(B) A telescope of 8 cm diameter and focal length of 64 cm.

(C) A telescope of 5 cm diameter and focal length of 100 cm.

(D) A telescope of 4 cm diameter and focal length of 40 cm.

B) A telescope of 8 cm diameter and focal length of 64 cm.

Which of the following object is the largest in size?

(A) Polaris

(B) Earth

(C) Milky Way Galaxy

(D) Sun

(E) Jupiter

C) Milky Way Galaxy

How long does it take for the Sun to complete one circle along the ecliptic

(A) 26,000 years

(B) one year

(C) one month

(D) one day

B) one year

______ has (have) lower photon energy than visible light.

(A) Gamma-rays

(B) Radio waves

(C) X-rays

(D) Ultraviolet light

B) Radio waves

If continuous spectrum light from a star passes through a cool low density gas on its way to your telescope,

____ spectrum is seen.

(A) an emission

(B) an absorption

(C) a continuous

B) an absorption

A plot of the continuous spectra of five different stars is shown in the figure below. Based on these spectra,

which of the stars has the lowest temperature?

Whichever star has the lowest intensity, and the longest wavelength.

As Earth rotates, the apparent motion of a star at the celestial equator as seen in the northern hemisphere in

a period of a day is

(A) rising in due east and setting in due west.

(B) a wobble back and forth in a straight line.

(C) a straight line across the sky.

(D) almost fixed at a point above the northern horizon.

A) rising in due east and setting in due west.

Why are some solar eclipses annular (with all but an annular ring of the Sun obscured) rather than total (with

the whole Sun obscured)?

(A) The Earth is sometimes farther away from the Sun and the Moon is unable to cover the whole Sun.

(B) The Sun is larger during times of greater solar activity (flares and sunspots), and then the Moon covers only

the central portion of the Sun.

(C) The Moon is sometimes farther away from the Earth so that the Moon's angular diameter is less than that of

the Sun at this time.

(D) The Moon's shadow (umbra) passes just north or south of the Earth, causing only an annular or ring eclipse.

C) The Moon is sometimes farther away from the Earth so that the Moon's angular diameter is less than that of the Sun at this time.

An observer in the Northern Hemisphere takes a time exposure photograph of the night sky. If the illustration

depicts the photograph taken by the observer, which direction was the camera pointing? (star is above the horizon)

C) North

If a light-emitting object is moving towards you, you observe its wavelengths to be ________ its wavelengths

if it were at rest.

(A) the same as

(B) longer than

(C) shorter than

C) shorter than

The hot, dense gas existing in the Sun emits energy

(A) mostly at the longest and shortest wavelengths, less in between.

(B) at all wavelengths uniformly.

(C) only at certain wavelengths and no others.

(D) at all wavelengths, with a peak at one particular wavelength (color).

D) at all wavelengths, with a peak at one particular wavelength (color).

The ecliptic crosses the celestial equator at

(A) the meridian.

(B) two points, known as solstices.

(C) two points, known as equinoxes.

(D) one point only, known as the vernal equinox

C) two points, known as equinoxes

Violet light differs from ultraviolet light in that violet light

(A) travels more slowly (through a vacuum) than ultraviolet light.

(B) travels more quickly (through a vacuum) than ultraviolet light.

(C) has a shorter wavelength than ultraviolet light.

(D) has a longer wavelength than ultraviolet light.

D) has a longer wavelength than ultraviolet light.

An apparent eastward motion of a planet from night to night compared to the background stars (as viewed

from Earth) is referred to as

(A) retrograde motion.

(B) precession.

(C) rising (if in the east) or setting (if in the west).

(D) direct/prograde motion.

D) direct/prograde motion (west to east)

A light year is a measure of

(A) distance

(B) force

(C) time

(D) speed

(E) mass

A) distance

A.U - equivalent to_____milllion kilometers

Astronomical units

153

Light years - The distance that ____ can travel in __ year, which is ____ trillion km

light, 1, 9.46

Ecliptic plane - plane of the earths ____ around the sun

orbit

Axis tilt - amount by which a planet's ___ is tilted

amount by which a planets axis is tilted

How do starts move in our solar system ___ r___

At random

How to galaxies move - t_____ us or a______

towards, away

What is a constilation - a region in the S___

sky

celestial sphere - imaginary sphere on which objects in the sky a____ to r___ when observed from the eart.

appear, reside

circumpolar - stars remain above the h___ and move c____ clockwise in the sky

horizon, counter

summer solstice - when the northern hemisphere is t___ away from the s__ and recieves most d____ sunlight

tilted, sun, direct

winter solstice - when the southern hemisphere is t____ towards the s__ and it recieves most d___ sunlight

tilted, sun, direct

Equinox - southern or northern hemisphere is s_____ tilted t___ or a__ the/away sun

slightly, tilted, away

precession - gradual w____ that changes the o____ of earths axis

wobble, orientation

Lunar phases - description of m___ seen from Earth

moon

Eclipse - when an astronomical o___ casts a s___ on another o___

object, shadow, object

Lunar eclipse - when the earth lies d___ between the m____ and the s____, so the earth's s____ falls on the m____

directly, moon, soon, shadow, moon

Solar eclipse - when the moon lies b_____ the s___ and e____, so the moon's s___ falls on the e___

between, sun, earth, shadow, earth

Penumbra - lighter, outlying r_____ of a shadow

region

Umbra - the d____ region of a shadow

darker

retrograde motion - stars seem as if they are m____ b____

moving, backwards

ptolemic model - believed that all other planets moved a___ in c____which o___ around the e___

earth was the c___ of the solar s__

around, circles, orbited, earth

center, system

Eratosthenes - figured out the c_____ of the earth, using the s____ of 7 d___ to estimate

circumference, shadow, degrees

Copernicus - created the h____ model.

He had the capability of c_____ distances to p____

heliocentric/sun oriented

calculating, planets

ptolomy - synthesized previous g___ a____ (earth centered)

greeks, astronomy

Plato and Aristotle - key in f_____ greek m___ of the universe. Believed e____ was the center of the solar system.

formulating, model

earth

Tycho Brahe - best n___ e___ astronomer. Making precise observations. His data position of m___ allowed K___ to discover 3 laws of p____ motion

naked, eye, mars, keppler, planetary

Keppler - discovered ____ laws of planetary motion.

kepler's key discovery was that planetary orbits are not c___ but are special o__ orbits called e___

three, circular, oval, ellipses

Keppler's first law - the orbit of each p____ about the sun is an e___ with the sun at one f____.

second law - planets move f___ when close to the sun and s___ when farther away.

third law - more distant planets orbit the sun at a s____ average s___

planet, ellipse, focus

faster, slower

slower, speed

Galileo - helped to establish e______ as a key part of the s____method. He studied m___, including the idea i___ and the idea that all objects fall at the s___ r___. He also heard about a telescope and m____ a better one, that could see c____, m____ on the moon and h___ on the sun.

experimentation, scientific, movement, inertia, same, rate, made, craters, mountains hot spots.

Galileo - figured out that objects could o___ about other o____

orbit, objects.

Isaac Newton - first law -an object moves at a c___ velocity if there is no n___ force acting upon it.

second law - the acceleration of an object is directly p____ to the n__ force, acting upon it and in the d___ the f___ is applied.

third law - an opposite f___ is needed. For every action f___, there is an equal and o___ reaction force

constant, net, proportional, net, direction, force, , opposite

Energy - is needed to make anything, m___, c____, g____ or do anything interesting.

moved, changed, grow

Law of conservation energy - energy can be t____ from one object to another, or t____ from one type of e___ to another, but the total a_____ of energy is conserved.

transferred, transformed, energy, amount.

Types of energy - Energy of motion k____

heat energy - the intensity of heat energy is m___ by t____.

potential energy - an example d___. gravitational p____ e___

kinetic, measured, temperature

dam, potential, energy

chemical potential energy - c___, g_____ and c____

coal, gasoline and carbohydrates.

nuclear potential energy - ur__-- of nuclear r____

uranium, reactors

relative energy - called electromagnetic r____ where the energy is c____ by electric and magnetic fields across the v___ of space.

radiation, carried, vaccum

hypothesis - ed____ g___

educated, guess

Hallmarks of Science - modern science seeks e____ for observed phenomena that r__ soley on n____ causes.

science progresses through the c____ and t___ of models of nature that explain the o____ as simply as possible.

scientific model must make t____ predictions about natural phenomena that would f____ us to revise or abandon the model if the p____ do not agree with observations.

explanations, rely, natural, creation, testing, observations, testable, force, predictions.

Who wrote the Almagest

Ptolemy

Which ancient Greek thinker suggested (long before Copernicus) that the Earth is moving around the Sun

Aristarchus

The Geo-Centric model is based on the teachings of which Greek philosopher

Aristotle

The scientist who first made astronomical observations that showed the validity of the heliocentric model of the solar system was

Galileo

The most important observation made to validate (show it was true) the heliocentric model was

That Venus goes through a full set of phases

Why do we have seasons on Earth?

As Earth goes around the Sun and Earth's axis remains pointed towards Polaris, the Northern and Southern hemispheres alternately receive more and less direct sunlight

The point directly over your head is called

the zenith

Within a constellation, a recognizable pattern of stars is often called

an asterism

The Sun's apparent path around the celestial sphere is called

the ecliptic

How did Ptolemy's Geocentric model explain the retrograde motion of planets like Jupiter?

the planets moved on epicycles

Kepler found out that the orbit of a stable planet is always in the shape of

an ellipse

T or F? After Copernicus was done with his model, he was able to predict where a planet would be in the future with much more accuracy than the Ptolemaic model

False

Why didn't stellar parallax convince the ancient Greeks that the Earth was moving

Stellar parallax had not been observed yet

Copernicus was not happy with the Ptolemaic model for several reasons. One of which was how Ptolemy had put special restrictions on the motion of which two planets?

Mercury and Venus

Who was the 17th century astronomer that spent 20 years of his life collecting data on planet positions

Tycho Brahe

T or F? Kepler's third law states a relationship between the period of a planet and the size of the semi-major axis of the orbit

True

When a planet is closest to the Sun it (Hint: Kepler's Laws)

a. moves its slowest

b. feels less gravitational pull than average

c. moves its fastest

c. moves its fastest

A planet is said to be in retrograde when it moves in what direction compared to the background of stars:

a. Eastward

b. Westward

b. Westward

How did Copernicus account for the retrograde motion of the planets?

a. Planets move on an epicycle that in turn moves on a deferent that circles around Earth

b. Planets slow down, stop, and then reserve their orbital direction around the Sun

c. Inner planets orbit the sun faster and pass out outer planets as they orbit around the Sun

d. The sun and moon orbit Earth, whereas all the other planets orbit the sun.

c. Inner planets orbit the sun faster and pass out outer planets as they orbit around the Sun

Why is it summer in the Northern Hemisphere when it is winter in the Southern Hemisphere?

The Northern Hemisphere is tilted towards the Sun and receives more direct sunlight

Which of the following is not a phase of the moon?

a. first-quarter Moon

b. third-quarter Moon

c. half Moon

d. new Moon

e. full Moon

c. half Moon

One astronomical unit (AU) is about 150 million kilometers. How many miles is that?

About 93 million miles