Astronomy 1142 Quiz 1
By detailed study of an object's electromagnetic radiation, we may learn about
(All of the other answers are correct) -its velocity towards us or away from us -the chemical composition of its surface -its temperature
If the force of the Sun's gravity were suddenly turned off
The earth would continue to move, but in a straight line
What "shifts" when we have a Doppler shift?
Wavelength
How do you express the numbers 0.17 and 542 respectively using scientific notation?
1.7 X 10^-1; 5.42 X 10^2
A jar has a sample of a material with 1000 atoms. After one half-life, how many unstable atoms are left, on the average?
500 atoms
A person with a mass of 60kg goes to the moon. There he will have a mass of
60kg
The dark lines on the solar spectrum are known as ___ lines
Absorption
When a cool gas cloud is placed between an observer and a source of light which emits light of all wavelengths, the observer would see
An absorption spectrum characteristic of the gas cloud
In an atom, energy is emitted or absorbed in a spectral line when
An electron changes its orbit
The star Betelgeuse is red; the star Rigel is blue. What causes this difference in color?
Betelgeuse is cooler than Rigel
Newton deduced from the law of gravitation that the shape of an orbit is ___ with the ___ at one focus
Conic section, center of mass
According to Newton's first law of motion, an object which has no force acting on it will have a
Constant velocity
What is the main cause of tides on Earth
Differential gravitational pull of the Moon on the Earth
The most damaging blow to proponents of the Earth-centered Universe was dealt by Galileo's
Discoveries of the phases of Venus and Moons of Jupiter
A spectrum of an astronomical object can be used to identify the atoms present in that object since
Each kind of atom has its own pattern of energy levels
What keeps electrons and protons in an atom bound together?
Electromagnetic forces
Light is
Electromagnetic radiation
Kepler's first Law of Planetary Motion states that a planet will orbit on an ___ with the Sun located at ___.
Ellipse, One focus
If a glowing blackbody gets even hotter, then it
Emits more light at all wavelengths
The first person known to have looked at the heavens through a telescope was
Galileo
As a hot solid cools, Wein's Law says that the apparent color of the radiation it emits should
Get steadily redder
The most abundant elements in the Universe are
Hydrogen and Helium
The process of removing an electron from an atom is called
Ionization
The luminosity of a star
Is the rate at which it radiates energy
Atoms which differ in the number of neutrons present in their nucleus but have an identical number of protons present are known as
Isotopes
How does the apparent brightness of a light source depend on its distance from you?
It varies as the inverse square of the distance.
Newton's second Law of Motion showed that the acceleration of a body depends on
It's mass and the force on it
Kepler's third law states that the square of the orbital period of a planet is proportional to
Its orbital semimajor axis cubed
The Doppler shift in a star's spectrum gives us
Its radial velocity
The man who was able to explain the reason for Kepler's laws was
Newton
"For every action there is an equal and opposite reaction" is a statement of
Newton's third law of motion
From Earth, planet A subtends an angle of 5 arcseconds, and plane B subtends an angle of 10 arcseconds. If the radius of planet A equals the radius of planet B,
Planet A is twice as far as planet B
What statement is a consequence of the law of equal areas in equal times?
Planets move slower when farther from the Sun
Which two particles can be found in an atomic nucleus?
Proton and Neutron
Kepler's main contribution to astronomy was
Showing that planets on ellipses around the Sun
If the average speed f the atoms and molecules of gas in a box increases, then the
Temperature increases
The speeding up of the spinning of a figure skater when he moves his arms from an outstretched position to close beside his body illustrates
The conservation of angular momentum
The force of gravity between two objects varies directly with ___ and inversely as ___.
The masses, the square of the distance
If we measure the wavelengths of emission lines and absorption lines from the same gas, we find that (ignoring any Doppler shifts)
The wavelengths are the same.
Galileo demonstrated that when a heavy and a light body are dropped at the same instant, and the objects are such that the effect of air resistance on each object is equal,
They fall exactly at the same rate
