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Quiz 2
1.
• Not graded.
2.
• If you close one eye and hold out your index finger, your
finger appears to cover an object. If you switch eyes,
your finger no longer covers that object. What word best
describes this phenomenon?
1. Parallax
2. Zenith
3. arc-second
4. tilt of earth
2.
• If you close one eye and hold out your index finger, your
finger appears to cover an object. If you switch eyes,
your finger no longer covers that object. What word best
describes this phenomenon?
1. Parallax
2. Zenith
3. arc-second
4. tilt of earth
3.
• In class, we estimated the angular separation of two
points on the screen that were separated by 10 feet.
Suppose that these two points were separated by 1 AU.
How far away from the screen would you need to walk
so that the dots appeared to subtend 1 arc-second?
1. 1 parsec
2. 1 AU
3. 1 light-year
4. 3600 parsec
3.
• In class, we estimated the angular separation of two
points on the screen that were separated by 10 feet.
Suppose that these two points were separated by 1 AU.
How far away from the screen would you need to walk
so that the dots appeared to subtend 1 arc-second?
1. 1 parsec
2. 1 AU
3. 1 light-year
4. 3600 parsec
4.
• How many parsecs are in 5 light-years?
1. 1.53
2. 16.3
3. 3.26
4. 5
5 light - year
1 parsec
x
 1.53 parsec
1
3.26 light - year
Related Questions
5.
• If you traveled at one-half of the speed of light
for one year, how far would you have gone?
1. One-half of a light-year
2. 3.26 parsecs
3. To the outer edge of the solar system
4. One light year
Related Questions
• Would it be possible to hold a telephone
conversation with someone who was 10
light-years away?
6.
In the image, suppose that a star in the
constellation Cygnus appears exactly at an
observer's zenith (the dotted line) at 8 pm local
time. After 24 solar hours have passed, where
would the constellation appear to be?
1. East of the observer's zenith
2. At the observer's horizon
3. Exactly at the observer's zenith
4. West of the observer's zenith
Where is Cygnus 24 solar hours later?
1. West
2. East
3. Vertical
(Over the
Pacific Ocean)
A solar day is
longer than a
sidereal day.
After sidereal day
Cygnus is
overhead. To get
to a solar day,
continue rotating
for 4 minutes.
Related Questions
• Describe the position of
Cygnus after two solar
days. After 4 solar days.
After 366.2424 solar days.
• In the diagram to the right,
the instructor is always
pointing straight outward.
He rotates around while
moving to point 2. Will he
point first again at the
student in the back of the
room or the student on the
stage?
2.
Related Questions cont.
• Suppose B rolls without slipping
around A. Every so often, B
“looks” directly at the center of A.
When B has made it back to his
starting position, how many
times has he looked straight to
the left (at something distant).
How is this related to the
statement that in the time Earth
rotates 365.2425 times with
respect to the sun it will have
rotated 366.2425 times with
respect to the stars?
A
B
7.
• What causes the seasons on Earth?
1. The speed of Earth in its orbit
2. The tilt of Earth with respect to the moon
3. The distance from the sun
4. The tilt of Earth with respect to the ecliptic
7.
• What causes the seasons on Earth?
1. The speed of Earth in its orbit
2. The tilt of Earth with respect to the moon
3. The distance from the sun
4. The tilt of Earth with respect to the ecliptic
Related Questions
• Suppose Earth’s tilt were changed such
that instead of having the north pole tilted
towards the sun in summer, it tilted
towards the sun in September. What
would happen to the seasons?
8.
• What are two things that happen as a result of the tilt of
Earth with respect to the ecliptic?
1. Precession of Earth and distance of sun from Earth
2. Change in length of time sun is visible and distance of
sun from Earth
3. Change in length of time sun is visible and change in
how close sun gets to zenith at noon.
4. Change in height of sun in sky and distance of sun
from Earth
8.
• What are two things that happen as a result of the tilt of
Earth with respect to the ecliptic?
1. Precession of Earth and distance of sun from Earth
2. Change in length of time sun is visible and distance of
sun from Earth
3. Change in length of time sun is visible and change in
how close sun gets to zenith at noon.
4. Change in height of sun in sky and distance of sun
from Earth
9.
• What is special about the Tropic of Cancer?
1. Once a year, in December, the sun never sets.
2. Once a year, in December, the sun is exactly
overhead (at the observer's zenith).
3. Once a year, in June, the sun is exactly overhead (at
the observer's zenith).
4. Once a year, in December, the sun never rises.
9.
• What is special about the Tropic of Cancer?
1. Once a year, in December, the sun never sets.
2. Once a year, in December, the sun is exactly
overhead (at the observer's zenith).
3. Once a year, in June, the sun is exactly overhead (at
the observer's zenith).
4. Once a year, in December, the sun never rises.
Zenith for an
observer on
the Tropic of
Cancer is
shown.
Related Questions
• Actually, it is more accurate to say that
once a year someone at a certain location
will see the Sun exactly at their zenith.
That is, not everyone on the Tropic of
Cancer will see their sun at their zenith
once a year. Why?
10.
• What is the latitude of Fairfax, VA?
1. 35 degrees north
2. 38 degrees north
3. 77 degrees west
4. 38 degrees south
10.
• What is the latitude of Fairfax, VA?
1. 35 degrees north
2. 38 degrees north
3. 77 degrees west
4. 38 degrees south
I won’t ask you this on the exam,
but it is a good thing to know.
11.
• What is a sidereal day and and solar day?
1. A sidereal day is the amount of time it takes the sun to repeat its
position in the sky. A solar day is the amount of time it takes for a
star to repeat its position in the sky.
2. A solar day is the length of the day at the Tropic of Capricorn at
solstice. A sidereal day is the length of the day in summer.
3. A solar day is the amount of time it takes the sun to repeat its
position in the sky. A sidereal day is the amount of time it takes for a
star to repeat its position in the sky.
4. A sidereal day is the length of the day at the Tropic of Capricorn at
solstice. A solar day is the length of the day in summer.
11.
• What is a sidereal day and and solar day?
1. A sidereal day is the amount of time it takes the sun to repeat its
position in the sky. A solar day is the amount of time it takes for a
star to repeat its position in the sky.
2. A solar day is the length of the day at the Tropic of Capricorn at
solstice. A sidereal day is the length of the day in summer.
3. A solar day is the amount of time it takes the sun to repeat its
position in the sky. A sidereal day is the amount of time it takes for a
star to repeat its position in the sky.
4. A sidereal day is the length of the day at the Tropic of Capricorn at
solstice. A solar day is the length of the day in summer.
Related Questions
12.
• What is special about the equator?
1. Twice a year, on a day in December and June, a person who lives
on the equator will see the sun at their zenith at one time during that
day.
2. Three times a year, in September, March, and June, a person
who lives on the equator will see the sun at their zenith at one time
during the day.
3. At the equator the sun never sets in March or September.
4. Twice a year, on a day in September and March, a person who
lives on the equator will see the sun at their zenith at one time
during that day.
5. At the equator the sun never sets in June or December.
12.
• What is special about the equator?
1. Twice a year, on a day in December and June, a person who lives
on the equator will see the sun at their zenith at one time during that
day.
2. Three times a year, in September, March, and June, a person
who lives on the equator will see the sun at their zenith at one time
during the day.
3. At the equator the sun never sets in March or September.
4. Twice a year, on a day in September and March, a person who
lives on the equator will see the sun at their zenith at one time
during that day.
5. At the equator the sun never sets in June or December.
Related Questions
13.
• Are the moon's phases caused by Earth
casting a shadow on the moon?
1. No.
2. Yes.
13.
• Are the moon's phases caused by Earth
casting a shadow on the moon?
1. No.
2. Yes.
Related Questions
• Does Earth ever cast a shadow on the
moon? Every month?
14.
• In the following image, Earth and moon are shown from
above the north pole. Of the directions shown, which one
best represents the direction of sun's rays?
(The part the moon and Earth that are colored black are
not hit with any of the sun's rays.)
1. A
2. B
3. C
4. D
14.
• In the following image, Earth and moon are shown from
above the north pole. Of the directions shown, which one
best represents the direction of sun's rays?
(The part the moon and Earth that are colored black are
not hit with any of the sun's rays.)
1. A
2. B
3. C
4. D
Related Questions
• Why do I draw the sun’s rays as being
parallel? Wouldn’t they be at an angle to
each other?
15.
• Which of the following best describes science?
1. The collection of data
2. A system of knowledge covering only astronomy data obtained
only by the collection of telescope measurements.
3. A set of facts
4. A system of knowledge covering general truths or the operation of
general laws especially as obtained through the scientific method.
5. The underlying truth about the universe
15.
• Which of the following best describes science?
1. The collection of data
2. A system of knowledge covering only astronomy data obtained
only by the collection of telescope measurements.
3. A set of facts
4. A system of knowledge covering general truths or the operation of
general laws especially as obtained through the scientific method.
5. The underlying truth about the universe
16.
• If a set of measurements has very high bias, can
the set of measurements have a very high
accuracy?
1. No. If there is a high bias, then the average of
the measurements is far away from the true
value. In order to have high accuracy, you need
to have all measurements very close to the true
value.
2. Yes, if all of the measurements are clustered
close to each other.
16.
• If a set of measurements has very high bias, can
the set of measurements have a very high
accuracy?
1. No. If there is a high bias, then the average of
the measurements is far away from the true
value. In order to have high accuracy, you need
to have all measurements very close to the true
value.
2. Yes, if all of the measurements are clustered
close to each other.
17.
The diagram below was shown in class and it
represents the view after 24 solar hours had
elapsed from when the Earth was at its initial
position (the blue circle with a white square is
the initial position). If you draw this diagram
again after 24 more solar hours have passed,
how would you describe the position of
Cygnus?
1. After the first 24 solar hours, Cygnus was no
longer at my zenith. After 24 more solar hours,
Cygnus is now further from my zenith than it
was after the first 24 hours had elapsed.
2. After the first 24 solar hours, Cygnus was at
my zenith. After 24 more solar hours, Cygnus is
at my zenith again.
3. After the first 24 solar hours, Cygnus was
past my zenith. After 24 more solar hours,
Cygnus is back at my zenith again.
17.
The diagram below was shown in class and it
represents the view after 24 solar hours had
elapsed from when the Earth was at its initial
position (the blue circle with a white square is
the initial position). If you draw this diagram
again after 24 more solar hours have passed,
how would you describe the position of
Cygnus?
1. After the first 24 solar hours, Cygnus was no
longer at my zenith. After 24 more solar hours,
Cygnus is now further from my zenith than it
was after the first 24 hours had elapsed.
2. After the first 24 solar hours, Cygnus was at
my zenith. After 24 more solar hours, Cygnus is
at my zenith again.
3. After the first 24 solar hours, Cygnus was
past my zenith. After 24 more solar hours,
Cygnus is back at my zenith again.
Related Questions
• In what direction with respect to your
zenith? East or West?