Term
|
Definition
| the distance between two wave peaks |
|
|
Term
|
Definition
| the number of times per second that a wavelength vibrates up and down |
|
|
Term
| how does a light wave occur? |
|
Definition
| the vibration of electric and magnetic fields by interacting with particles in these fields |
|
|
Term
|
Definition
| the combination of electric field and magnetic field |
|
|
Term
| how are electric fields produced? |
|
Definition
| by charge and by changing magnetic fields |
|
|
Term
| how are magnetic fields produced? |
|
Definition
| by moving charges and by changing electric fields |
|
|
Term
| T/F Light is a self propagating entity |
|
Definition
|
|
Term
| light waves are characterized by... |
|
Definition
| a wavelength (unside down y) and a frequency (f OR v). |
|
|
Term
| what is the equation for finding the frequency of a wave? |
|
Definition
|
|
Term
| what is C in the wavelength equation? |
|
Definition
| (distance) the speed of light: 300,000 km/s OR 3×10^8 m/s |
|
|
Term
| what is C in the wavelength equation? |
|
Definition
| (distance) the speed of light: 300,000 km/s OR 3×10^8 m/s |
|
|
Term
| (frequency equation again) |
|
Definition
|
|
Term
| what is the wavelength of light measured in? |
|
Definition
nanometers (nm) or Ångström (Å)
1 nm = 10^-9 m
1 Å = 10^-10 m = 0.1 nm |
|
|
Term
| Visible light has wavelengths between... |
|
Definition
| 4000 Å and 7000 Å (400–700 nm) |
|
|
Term
| what can light appear as? |
|
Definition
|
|
Term
| what is a light particle? |
|
Definition
|
|
Term
| the equation for a photon's energy is... |
|
Definition
(A photon has a specific energy E, proportional to the frequency f:)
E = h×f
h = 6.626 x 10^-34 J·s
(is the Planck constant) |
|
|
Term
| T/F The energy of a photon depends on its light intensity |
|
Definition
|
|
Term
| The electromagnetic Spectrum |
|
Definition
|
|
Term
| (electromagnetic spectrum again) |
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
| How does the reflecting telescope work? |
|
Definition
| Concave mirror focuses light onto the focal plane |
|
|
Term
| almost all modern telescopes are... |
|
Definition
|
|
Term
| how does a refracting telescope work? |
|
Definition
| Lens focuses light onto the focal plane |
|
|
Term
| what is the focal length? |
|
Definition
distance from the center of the lens to the plane onto which parallel light is focused.
(if the focal length is short, the lense must be strongly curved) |
|
|
Term
| what does the secondary optics do? |
|
Definition
| is needed to re-direct light path towards back or side of incoming light path |
|
|
Term
|
Definition
| views and enlarges the small image produced in the focal plane of the primary optics |
|
|
Term
| What does the Light gathering power of a telescope depend on? |
|
Definition
the surface area A of the primary lens / mirror, proportional to diameter squared:
A = (pi)*(D/2)^2 |
|
|
Term
|
Definition
| minimum angular distance between two objects that can be separated |
|
|
Term
|
Definition
| alpha min = 1.22 (wavelength/D) |
|
|
Term
| what is a telescope's magnifying power? |
|
Definition
| the ability of a telescope to make the image appear larger |
|
|
Term
| the equation for determining magnifying power |
|
Definition
The magnification depends on the ratio of focal lengths of the primary mirror/lens (Fo) and the eyepiece (Fe):
M = Fo/Fe |
|
|
Term
| T/F: A larger magnification does not improve the resolving power of the telescope! |
|
Definition
|
|
Term
Which features of a telescope
determines its light gathering power? |
|
Definition
The diameter of the
primary optic |
|
|
Term
Which has the larger light-gathering power?
(A) A telescope of 6 cm
diameter and focal length of
100 cm.
(B) A telescope of 5 cm
diameter and focal length of
50 cm. |
|
Definition
| A (telescope with 6 cm diameter and focal length of 100) |
|
|
Term
|
Definition
Combination of the signals from several smaller telescopes to simulate one big mirror
alpha min = 1.22 wavelength/D |
|
|
Term
|
Definition
(CCD = Charge-coupled device)
-More sensitive than photographic plates
• Data can be read directly into computer memory, allowing easy electronic manipulations
-False-color image to visualize brightness contours |
|
|
Term
|
Definition
| black stars against a white sky |
|
|
Term
| what is used to split light up into the different wavelengths to produce a spectrum? |
|
Definition
|
|
Term
| when light is split up into different wavelengths, what do we see? |
|
Definition
|
|
Term
Spectral lines in a
spectrum tell us about what? |
|
Definition
the chemical composition and other
properties of the observed object. |
|
|
Term
______ is used to improve the
resolving power. |
|
Definition
|
|
Term
| A neutral atom always contains... |
|
Definition
the same number of
protons as it does
electrons. |
|
|
Term
| _____ is a set of rules that describes how atoms and subatomic particles behave. |
|
Definition
|
|
Term
|
Definition
| same # of protons, but a different # of neutrons |
|
|
Term
|
Definition
same # of protons, different # of electrons
(gives it a + or - charge: + charge, less electrons than protons, - charge, more electrons than protons) |
|
|
Term
| Just by analyzing the light received from a star, astronomers can retrieve information about a star’s… |
|
Definition
1.Total energy output
2.Surface temperature
3.Radius
4.Chemical composition
5.Velocity relative to Earth
6.Rotation period |
|
|
Term
An electron can be kicked into a higher
orbit when it_______ a photon with exactly the right energy. |
|
Definition
|
|
Term
| to move down an enery level, an electron must ____ a photon. |
|
Definition
|
|
Term
| T/F High frequency photons carry more energy than long wavelength photons. |
|
Definition
|
|
Term
| T/F All electromagnetic waves travel at the speed of light. |
|
Definition
|
|
Term
| T/F Different types of electromagnetic radiation are fundamentally different types of waves |
|
Definition
|
|
Term
| How does the light-gathering power of a 6 m telescope compare with that of the human eye? (Hint: Assume that the pupil of your eye can open to about 0.8 cm.) |
|
Definition
-convert 6m to cm =600 cm
-divide 600 by .8 cm
-square the answer!
answer: 562500 |
|
|
Term
| A single photon of which color has the greatest amount of energy? |
|
Definition
|
|
Term
| The entire electromagnetic spectrum can be divided into seven bands: radio, microwave, infrared, visible, ultraviolet, X ray, and gamma ray (from longest to shortest wavelength). To which of these two bands is Earth's atmosphere the most transparent? |
|
Definition
|
|
Term
| Which theoretical power of an optical telescope is determined by the diameter of the primary mirror or lens? |
|
Definition
| light gathering power and resolving power |
|
|
Term
| Radio telescopes are often connected together to do interferometry. What is the primary problem overcome by radio interferometry? |
|
Definition
|
|
Term
| Rank the following colors of visible light in order of increasing wavelength: blue, green, red, yellow. |
|
Definition
|
|
Term
| Rank the following colors of visible light in order of increasing frequency: green, red, violet, yellow |
|
Definition
| red, yellow, green, violet |
|
|
Term
| Rank the following types of electromagnetic radiation in order of decreasing wavelength: infrared, gamma-ray, radio, ultraviolet, visible. |
|
Definition
| radio, infrared, visible, ultraviolet, gamma-ray |
|
|
Term
| In the Bohr model, where are the electrons located? |
|
Definition
| In orbits around the nucleus |
|
|
Term
| In atomic excitation, electrons jump between which two orbits? |
|
Definition
| From a lower orbit to a higher one |
|
|
Term
| A photon is emitted during which atomic process? |
|
Definition
|
|
Term
| Describe what an absorption spectrum looks like. |
|
Definition
A continuous spectrum with specific colors of light missing.
(The missing colors represent specific wavelengths of light that were absorbed by the thin gas.) |
|
|
Term
| The light bulb here serves as the blackbody. What is a characteristic of blackbodies? |
|
Definition
|
|
Term
| T/F A star has an emission spectrum, since it is a blackbody surrounded by a thinner atmosphere. |
|
Definition
False.
The star produces an absorption spectrum |
|
|
Term
| Light and sound waves from a moving source are ________ in the direction of movement. |
|
Definition
compressed--blue light
(Doppler Effect) |
|
|
Term
| The light or sound waves from a moving object increase in frequency when.. |
|
Definition
| it is moving toward you. (Doppler Effect) |
|
|
Term
| What does an observer moving at the same speed with a sound source measure? |
|
Definition
no change in the sound
(Doppler Effect) |
|
|
Term
| The temperature of a gas is a measure of... |
|
Definition
| average motion of its atoms |
|
|
Term
| Which subatomic particle has a negative charge? |
|
Definition
|
|
Term
| which color represents the lowest surface temperature for a star? |
|
Definition
|
|
Term
| which color represents the highest surface temperature for a star? |
|
Definition
|
|
Term
| An atom that is ionized must have... |
|
Definition
| either more electrons that protons or more protons than electrons |
|
|
Term
| T/F The nucleus of an atom contains 99.9% of an atom's mass |
|
Definition
|
|
Term
| T/F The nucleus of an atom It contains all of an atom's positive charge. |
|
Definition
|
|
Term
| What conditions produce a dark (absorption line) spectrum? |
|
Definition
| light from a continuous spectrum source passing through a cooler low-density gas |
|
|
Term
| You research the star Sirius and find that its spectral lines are blue-shifted. What does this tell you about Sirius? |
|
Definition
| It has a radial velocity that is toward us. |
|
|
Term
| Which area is of super-hot gas that extends farthest from the Sun? |
|
Definition
|
|
Term
| What are some characteristics that relate to sunspots? |
|
Definition
-Areas of lower temperatures on the Sun's surface
-Auroras
-The Sun's magnetic field |
|
|
Term
| What is the hottest part of the Sun? |
|
Definition
the Core
(Nuclear fusion creates temperatures in the millions of degrees.) |
|
|
Term
| Which layer of the sun's atmosphere contains the cooler low-density gas responsible for absorption lines in the sun's spectrum? |
|
Definition
|
|
Term
| T/F (Stars) Heat flows from hot to cool regions. |
|
Definition
|
|
Term
| T/F The temperature of a star can be roughly estimated from its color. |
|
Definition
|
|
Term
| T/F Stars emit light mostly from their surfaces. |
|
Definition
|
|
Term
| T/F Hotter stars radiate more energy at higher frequencies. |
|
Definition
|
|
Term
| T/F Hotter stars have a longer maximum intensity wavelength. |
|
Definition
|
|
Term
| T/F Black body radiators are generally cool. |
|
Definition
|
|
Term
| T/F Temperature is a measure of the heat produced by a star |
|
Definition
|
|
Term
| If a star has a surface temperature of 12,000 K, at what wavelength will it radiate the most energy? |
|
Definition
| (2.9 * 10^6)/ 12000 K = 241.666 nm |
|
|
Term
| Archeologists & anthropologists surmise that ancient cultures studied astronomy to... |
|
Definition
– keep time
– agricultural
– religious |
|
|
Term
| what did Pythagoreus believe? |
|
Definition
1.Spherical earth (spheres were considered
the most perfect of the geometrical solids)
2. Stars and planets were contained in
spheres (previous slide, Fig. 3.12)
3. Earth was at the center (geocentric) |
|
|
Term
|
Definition
All natural
motion is circular
• Reason is more
important than
observation |
|
|
Term
| What did Aristotle believe everything was composed of? |
|
Definition
elements
– earth
– water
– air
– fire
– quintessence |
|
|
Term
| What are the 2 parts Aristotle believe that the universe can be divided into? |
|
Definition
1. Imperfect, changeable Earth
2. Perfect heavens (described by spheres) |
|
|
Term
Aristotle’s geocentric model had several observations
supporting it: |
|
Definition
1. The earth would naturally form a sphere.
2. Objects thrown in the air come back down, so
the earth must not be rotating.
3. There is no stellar parallax (if earth moved
around sun, then apparent position of the stars
should change during the course of a year). |
|
|
Term
|
Definition
the apparent motion of an
object due to the motion of
the observer. |
|
|
Term
| What did Eratosthenes do? |
|
Definition
| He measured the circumference of the earth |
|
|
Term
| What was one major flaw of a geocentric universe? |
|
Definition
|
|
Term
| What was the solution to retrograde motion? |
|
Definition
|
|
Term
An apparent westward motion of a planet in the sky
compared to the background stars (as viewed from the
Earth) when observed on successive nights is referred
to as... |
|
Definition
|
|
Term
| who introduced the ideo of epicycles? |
|
Definition
|
|
Term
| Who proposed the heliocentric universe? |
|
Definition
|
|
Term
T/F Classical Greek astronomers believed the
motions of the heavens could be described by
uniform circular motion. |
|
Definition
|
|
Term
Who Used the precise
observational tables of
Tycho Brahe to study
planetary motion
mathematically? |
|
Definition
|
|
Term
| What two concepts did Kepler abandon? |
|
Definition
1. circular motion
(Planets move around the Sun on elliptical
paths, with non-uniform velocities.)
2. uniform motion |
|
|
Term
| What are 3 major achievements of Isaac Newton? |
|
Definition
1. Invented Calculus as a necessary tool to solve mathematical
problems related to motion
2. Discovered the three laws of motion
3. Discovered the universal law of mutual gravitation |
|
|
Term
| What does The Universal Law of Gravity state? |
|
Definition
| Any two bodies are attracting each other through gravitation, with a force proportional to the product of their masses and inversely proportional to the square of their distance |
|
|
Term
| What is the formula for gravity? |
|
Definition
F = –G *(Mm/r^2)
(G=9.8 m/s^2) |
|
|
Term
The _____ of an object is a measure of the amount of
matter it contains. On the other hand _____ is a
measure of the gravitational force on an object. |
|
Definition
|
|
Term
The force of gravity from one object extends to infinity
never going to zero. When we say that gravitation is
universal we mean that.... |
|
Definition
all material objects in the
universe exert gravitational
forces on one another |
|
|
Term
If the mass of the Earth decreased by a factor of
two with no change in radius, your weight would... |
|
Definition
decrease by a factor
of 2. |
|
|
Term
| how do satellites remain in the same place over earth? |
|
Definition
Geo- Synchronous Orbits
(24 hour orbit) |
|
|
Term
|
Definition
| Caused by the difference of the Moon’s gravitational attraction on the water on Earth |
|
|
Term
| T/F The Sun is also producing tidal effects, about half as strong as the Moon. |
|
Definition
|
|
Term
| when do neap tides occur? |
|
Definition
| first and third quarter moon |
|
|
Term
| when do spring tides occur? |
|
Definition
|
|
Term
| what is the primary objective to a telescope? |
|
Definition
| gather large amounts of light |
|
|
Term
| The centers of granules... |
|
Definition
are hot material rising to
the photosphere from
below. |
|
|
Term
|
Definition
| the visible consequence of convection |
|
|
Term
T/F Most of the visible light from the sun
originates in the photosphere. |
|
Definition
|
|
Term
| energy generated in the sun's center must be transfered outward. this is done where and how? |
|
Definition
| in the photosphere through convection |
|
|
Term
| what is the outermost layer of the sun? |
|
Definition
|
|
Term
| from outermost to innermost, name the layers of the sun |
|
Definition
| corona, chromosphere, photosphere, core |
|
|
Term
| what is the energy generation process in stars called? |
|
Definition
|
|
Term
|
Definition
| the fusing of two or more muclei to produce heavier ones |
|
|
Term
| what is a blackbody spectrum? |
|
Definition
The spectrum of a star’s
light is approximately a
thermal spectrum.
A perfect blackbody
emitter would not reflect
any radiation, thus the
name “blackbody”. |
|
|
Term
| T/F The hotter an object is, the more luminous it is |
|
Definition
|
|
Term
The peak of the blackbody spectrum shifts towards
______ wavelengths when the temperature increases |
|
Definition
|
|
Term
Why don't we see hydrogen Balmer lines in the spectra
of stars with temperatures of 45,000 K? |
|
Definition
The stars are hot enough that
most of the hydrogen is ionized
and the atoms can not absorb
energy. |
|
|
