UCSB ASTRO FINAL EXAM QUESTIONS
AND ANSWERS
When the Moon is a thin crescent, what is the phase of Earth as seen from
the Moon? - -A Gibbous (mostly full) Earth
- Saturn moves in an orbit around the Sun with a period of 30 years. How
many degrees does it move on the Celestial Sphere in one year? - -12
Degrees - 360/30=12degreeperyear
- You are on the equator. Where in the sky is Polaris? - -Due north on the
horizon
- Io and Europa are big Jovian moons. Io's orbit about Jupiter has a
semimajor axis of 422,000 km, and a period of 1.77 days. Europa's orbit size
about Jupiter is 671,000 km. What is the period? - -3.54 days
- How long does night last on the moon? - -2 weeks
- It is warmer in summer than winter because - -The Sun is higher in the sky
and the days are longer
- The Earth's shadow falling on the Moon is the reason we see - -Lunar
Eclipses
- The gravity on Mars is weaker than that on Earth. Which is true? - -An
astronaut would have the same mass on Mars, but would weigh less
- A theory is like a law of physics that is speculative. T or F - -False
- The gravitational acceleration on the Earth's surface is 32
feet/second/second. What would it be on the surface of a planet with the
same size, but twice the mass? - -64 feet/second/second - 32*2=64
ft./sec^2
- The average distance to the Sun is 93 million miles, and the Sun subtends
an angle of ½ degree. Calculate its approximate diameter. - -800,000 miles.
- .5*3600=1800arcseconds. 1800*93mil/200000=837000
- What is the "Observable Universe"? - -Everything within the "cosmic
horizon"
- In Newton's law of universal gravitation, F = G M m / r2 , which defines the
force between Earth with mass M and an orbiting satellite of mass m at a
, distance r from Earth, G... - -is a constant, throughout all observable space
and time.
- How strong is the gravitational force that acts on an astronaut in the Space
Shuttle in a circular orbit 300 km above Earth's surface? - -Almost (but not
quite) as strong as when the astronaut is standing on the surface of Earth
- An astronaut is floating freely in space. If they were to push on a nearby
spaceship, what would happen? - -Both the astronaut and the spaceship
would move, but in opposite directions.
- Venus shows changes in angular size, and also shows phases similar to
those of the Moon. When Galileo first saw these changes, he concluded that -
-Venus orbits the Sun.
- We learned that light energy is quantized; that is, for a given frequency,
the energy in light must be an integral multiple of a particular number of
Joules of energy given by E = hν. Here ν is the frequency of light. How many
Joules of energy are contained in a green unit of light (a photon) ? Green
light has a wavelength of around 500 nm - -3. 97 × 10 Joules --
500/10^9=wavelength in meters. E=(6.26*1-^-
34)*(2.98*10^8/5.96*10^14)=3.97*10^-19.
- The vernal equinox in the Northern hemisphere is that time of the year
when the - -Sun crosses the equatorial plane, or celestial equator, moving
northward.
- Suppose that at the same time on the same night we see one supernova (a
star exploding) in the Andromeda galaxy, 2 million light-years away from us,
and another in the galaxy M82, 6 million light-years away from us. Which of
the following statements is correct? - -The supernova in the Andromeda
galaxy actually occurred after the one in M82.
- The "block and feather" demonstration showed that in the absence of air
friction: - -The force of gravity must be proportional to the mass -
- The intersection of the plane of the Earth's orbit with the celestial sphere is
known as - -the ecliptic -
- You will see that when the Sun dies, it will leave behind its very compact
core, an Earth-sized "White Dwarf" star which retains 60% of the Sun's mass
(The rest blows off into space). What would you weigh on such a white dwarf,
if on Earth you weigh 600 N (about 135 lbs) ? - -1.20 x 10^8 N
- What do scientists mean by the word Theory? - -An idea which allows you
to try to predict future events
AND ANSWERS
When the Moon is a thin crescent, what is the phase of Earth as seen from
the Moon? - -A Gibbous (mostly full) Earth
- Saturn moves in an orbit around the Sun with a period of 30 years. How
many degrees does it move on the Celestial Sphere in one year? - -12
Degrees - 360/30=12degreeperyear
- You are on the equator. Where in the sky is Polaris? - -Due north on the
horizon
- Io and Europa are big Jovian moons. Io's orbit about Jupiter has a
semimajor axis of 422,000 km, and a period of 1.77 days. Europa's orbit size
about Jupiter is 671,000 km. What is the period? - -3.54 days
- How long does night last on the moon? - -2 weeks
- It is warmer in summer than winter because - -The Sun is higher in the sky
and the days are longer
- The Earth's shadow falling on the Moon is the reason we see - -Lunar
Eclipses
- The gravity on Mars is weaker than that on Earth. Which is true? - -An
astronaut would have the same mass on Mars, but would weigh less
- A theory is like a law of physics that is speculative. T or F - -False
- The gravitational acceleration on the Earth's surface is 32
feet/second/second. What would it be on the surface of a planet with the
same size, but twice the mass? - -64 feet/second/second - 32*2=64
ft./sec^2
- The average distance to the Sun is 93 million miles, and the Sun subtends
an angle of ½ degree. Calculate its approximate diameter. - -800,000 miles.
- .5*3600=1800arcseconds. 1800*93mil/200000=837000
- What is the "Observable Universe"? - -Everything within the "cosmic
horizon"
- In Newton's law of universal gravitation, F = G M m / r2 , which defines the
force between Earth with mass M and an orbiting satellite of mass m at a
, distance r from Earth, G... - -is a constant, throughout all observable space
and time.
- How strong is the gravitational force that acts on an astronaut in the Space
Shuttle in a circular orbit 300 km above Earth's surface? - -Almost (but not
quite) as strong as when the astronaut is standing on the surface of Earth
- An astronaut is floating freely in space. If they were to push on a nearby
spaceship, what would happen? - -Both the astronaut and the spaceship
would move, but in opposite directions.
- Venus shows changes in angular size, and also shows phases similar to
those of the Moon. When Galileo first saw these changes, he concluded that -
-Venus orbits the Sun.
- We learned that light energy is quantized; that is, for a given frequency,
the energy in light must be an integral multiple of a particular number of
Joules of energy given by E = hν. Here ν is the frequency of light. How many
Joules of energy are contained in a green unit of light (a photon) ? Green
light has a wavelength of around 500 nm - -3. 97 × 10 Joules --
500/10^9=wavelength in meters. E=(6.26*1-^-
34)*(2.98*10^8/5.96*10^14)=3.97*10^-19.
- The vernal equinox in the Northern hemisphere is that time of the year
when the - -Sun crosses the equatorial plane, or celestial equator, moving
northward.
- Suppose that at the same time on the same night we see one supernova (a
star exploding) in the Andromeda galaxy, 2 million light-years away from us,
and another in the galaxy M82, 6 million light-years away from us. Which of
the following statements is correct? - -The supernova in the Andromeda
galaxy actually occurred after the one in M82.
- The "block and feather" demonstration showed that in the absence of air
friction: - -The force of gravity must be proportional to the mass -
- The intersection of the plane of the Earth's orbit with the celestial sphere is
known as - -the ecliptic -
- You will see that when the Sun dies, it will leave behind its very compact
core, an Earth-sized "White Dwarf" star which retains 60% of the Sun's mass
(The rest blows off into space). What would you weigh on such a white dwarf,
if on Earth you weigh 600 N (about 135 lbs) ? - -1.20 x 10^8 N
- What do scientists mean by the word Theory? - -An idea which allows you
to try to predict future events
