Exam 1
if x/3 = 15/9 then
15*3/9 = x=5
Light travels 3 x 10^5 meters every second. That number in words is
300,000 meters
the mass of your text book
= 1 kg
10 cm^2
= 1,000 mm^2
5.25 x 10^4 - 3.50 x 10^4
= 1.75 x 10^4
8 x 10^6/2 x 10^2
= 4 x 10^4
7,000,000,000,000,000,000,000,000
= 7 x 10^24
the mass of Dr. Rabbani
= 70 kg
(4 x 10^4)(2 x 10^6)
= 8 x 10^10
5 x 10^8 + 3 x 10^8
= 8 x 10^8
0.0009
= 9 x 10^-4
Credit for the discovery of Neptune is shared by two astronomers. They are:
Adams and Leverrier
When the authors of our textbook say that astronomers are like police detectives trying to solve crimes, they are explaining that:
Both astronomers and detectives must test their hypothesis against any evidence that they gather
The first person who regularly turned a telescope to astronomical observations (and published his observations) was:
Galileo Galilei
the scientist who worked out the mathematics of the connections between electricity, magnetism, and light in the 19th century was:
James Clerk Maxwell
The idea that atoms radiate energy only when their electrons move from higher to lower energy levels was first advanced by:
Niels Bohr
the planet in our solar system whose orbit actually brings it inside the orbit of another planet is:
Pluto
The earliest telescopes used by astronomers were:
Refractors
of the following, which consists of electro-magnetic waves with the shorts wavelength
TV transmissions bringing us Monday night football
The Earth's escape speed (the speed you need to get away forever) is about 25,000 milers per hour. Escape speed depends on the gravity of the object trying to hold the spacecraft from escaping. Based on your understanding of gravity, how will the escape speed from the Moon compare to the escape speed form Earth?
The Moon's escape speed will be smaller than Earth's
After a long night of cramming for a test, your college room-mate hits his head forcefully against the wall of your room in despair. According to Newton's 3rd Law, as he exerts a force against the wall, there must be an equal and opposite force. How does that opposite force show itself in this case?
The wall exerts a force on your room-mate's head and he has a headache
the 17th century astronomer who kept a roughly 20 year continuous record of the positions of the sun, moon, and planets was:
Tycho Brahe
What specific event really made it possible for the three laws of planetary motions to be discovered?
Tycho Brahe died and his assistant was able to get full access to his data
a hertz is
Unit of frequency
The largest refracting telescope in the world, financed by a Chicago millionaire in the 1890's, is at the:
Yerkes Observatory
which of the following has the greatest average energy of random atomic and molecular motion?
a cube of the sun
Which of the following has the greatest density?
a cubic meter of lead
Newton showed that to change the direction in which an object is moving, one needs to apply:
a force
the location of the earth in the milky way galaxy is
a little less than 30,000 LY from the center
which of the following statements about photons is FALSE
a photon of visible light cannot pass through the atmosphere of the earth, and thus cannot be seen at the earth's surface
a large body in space that consistently makes its own light (instead of merely reflecting another body's light) is called
a star
the asteroid belt
a zone where rocky chunks orbit between Mars and Jupiter
An astronomer observes two ordinary stars. The first one turns out to be twice as hot as the second. This means that the first one radiates:
about 16 times the energy of the second
To go from a lower level in an atom to a higher level, an electron must
absorb a photon of energy
Two stars are giving off electromagnetic radiation. The hotter star will:
all of the above
What do many people consider Isaac Newton one of the greatest scientists who ever lived?
all of the above
the smallest piece of an element (like gold or lead) that still has all the properties of that element is called
an atom
We know that the orbit of a stable planet around a star like the sun is always in the shape of
an ellipse
An artist who likes working with sources of light decides to make a modern sculpture out of electrified glass tubes that contain very thin (rarified) neon gas. When the sculpture is finished, and the electricity is turned on, the tubes glow with a rich red color. What we are seeing is:
an emission spectrum
The laws of nature (as determined by scientists)
apply both on earth and among the stars
When a star or galaxy is moving away from us, we observe the Doppler effect by seeing the lines in its spectrum
become darker and darker (like a blackbody)
After a nice dinner around the campfire on a camping trip, you and a friend decide to get away from the fire to observe the stars. As you get farther and farther away, you see the brightness of the fire:
decrease as the distance squared
according to Kepler's third law, there is a relationship between the time a planet takes to revolve around the sun and its
distance from the sun
The way that scientists know that a hypothesis in astronomy is a reasonable description of nature is to
do experiments and observations about the predictions of the hypothesis
Even with the best and largest telescopes, we can't see all the stars in the Milky Way Galaxy, even though these same telescopes can show us other galaxies. Why is that?
dust in space between stars builds up over large distances and blocks the light of stars behind the dustier parts of the milky way
in the 19th century, it became clear that magnetism was not a separate force, but was always produced by the action of
electric charges that were in motion
By the term universe, astronomers mean
everything that we can observe
According to Kepler's 2nd Law, comets (which have eccentric orbits) should spend a lot more of their time:
far from the sun
One of the great triumphs of spectroscopy was when astronomers identified a new element in the Sun (one that was only later found on Earth). Today, this element is called:
helium
Atoms typically consist of electrons, protons, and neutrons. The most common isotope of one element, however, only has two of these three types of particles. This element is:
hydrogen
You are on a camping trip, far away from city lights. You look up into the dark night sky, and see lots of stars, some brighter, some dimmer. All the stars you see with your unaided eye are
in the Milky Way Galaxy
You are alone in a large, completely dark auditorium on Earth. What kind of telescope should I use from the other side of the auditorium to detect the electromagnetic radiation emitted by your body?
infra-red
When an atom has lost one or more electrons, it is said to be:
ionized
which of the following statements about infrared radiation is TRUE
it was first discovered in 1800 in an experiment using sunlight and thermometers
Which of the following statements about the force of gravity is FALSE
its strength is inversely proportional to the mass: the more mass, the less gravity
To figure out what you weigh on the surface of the moon (how much gravity there pulls you downward, you need to know
just the size of the moon's center to its surface
We have two waves of light, A and B. Wave A has a higher frequency than wave B. Then wave B must have:
longer wavelength
how do astronomers learn what elements are present in a given star?
look at the absorption lines in its spectrum
the width of a door is about 1
m
the thickness of a dime is about 1
mm
In Newton's Law of Gravity, the force of gravity goes up the:
more than on above
when white light passes from the air into a different medium such as glass, it:
more than one of the above
Small changes in the orbits of planets caused by the gravitational pull of the other planets in the solar system are called:
perturbations
which of the following as the longest wavelength
radio waves
how could you make an ordinary atom that is minding its own business into an ion?
remove one or more electrons from the atom
Astronomical observatories have been available since ancient times, and many cultures set aside special sites for astronomical observations. The thing modern observatories have that was missing form these older observations until about 1610 was:
telescopes
The Stephan-Boltzmann Law relates the energy flux coming from blackbody (such as a star) to its:
temperature
in 1911 Ernest Rutherford did a famous experiment using fast-moving alpha particles as bullets and very thin gold foil as a target. The results of this experiment showed that:
that the nucleus of an atom was tiny compared to the size of the whole atom
Why do astronauts (and cans of soft drink) float around in the Shuttle instead of falling
the Shuttle is falling around the Earth (and everything aboard is in free fall)
the astronomical unit (AU) as defined by astronomers 9s
the average distance between the earth and the sun
A light year is
the distance light travels in one year
In an ellipse, the ratio of the distance between the foci and the length of the major axis is called:
the eccentricity
the ground state of an atom is
the electron orbit with the lowest possible amount of energy
of these, which is closest to us?
the moon
the natural object (not one that humans built) in space that's closest to earth is
the moon
For scientists, an element (like gold) is defined by
the number of protons in its nucleus
Most ultraviolet radiation does not penetrate to the Earth's surface. Instead it is absorbed in:
the ozone layer
The star that provides energy for life on Earth is
the sun
of these, which is the largest?
the universe
(in the absence of a strong magnetic field), what is the chief factor that determines what type of electromagnetic radiation objects give off
their temperature
Why do satellites launched into low-Earth orbits not remain there indefinitely?
they lose speed due to friction with the upper layers of the Earth's atmosphere
All molecules (like molecules of water or carbon dioxide) are made up of
two or more atoms
the light which allows you to see this very interesting exam is made up of waves. In these waves, the distance between crests is called the:
wavelength
In the future, several students living on board a space station decide to have a race among different types of electromagnetic radiation. Which of the following travels through space the fastest?
you can't fool me, all these travel through space at the same speed
Which of the following is the Earth NOT located in?
you can't fool me, we are located in all of the above