Exam 2 Flashcards
Light waves and photons carry ________, and the strength of ________ is often given as a power.
Energy; light
Why are some people color blind?
Color is a perception.
List the three primary light colors.
Red, blue, green
Note: The 3 primary art colors are cyan, magenta, and yellow.
Color that contains every other color.
White
Color representing absence of light.
Black
Light/Matter Interactions: light leaves matter.
Emission
Light/Matter Interactions: light enters matter.
Absorption
Light/Matter Interactions: light travels through matter.
Transmission
Light/Matter Interactions: light bounces off of matter.
Reflection
Light/Matter Interactions: random motions as light bounces off matter; during reflection/transmission.
Scattering
A mirror is an example of ________ reflection.
Secular
The color we see as an object’s color is ________, and all other colors are ________.
Reflected; absorbed
What color(s) does an orange shirt reflect? What color(s) does it absorb?
Orange; all other colors
Properties of Light: The distance from one peak to the next (or one trough to the next) in a light pattern.
Wavelength
In order to start, wavelengths require a:
Disturbance
Property of medium; propagate waves.
Wave speed
How often a light pattern will repeat.
Frequency
Require a physical medium to propagate through. (Hint: no one in space can hear you.)
Mechanical waves
Self-sustaining waves propagating through the electromagnetic field.
Electromagnetic waves
When a wavelength becomes longer, the frequency is ________.
Lower
Light is carried by ________.
Photons
List the electromagnetic spectrum from longest to shortest wavelength.
Radio, microwave, infrared, visible, ultraviolet, x-ray, and gamma ray.
Higher frequency waves have ________ energy.
Higher
Positively charged particle in the nucleus.
Proton
Neutral charged particle in nucleus.
Neutron
Negatively charged particle surrounding nucleus.
Electron
Atoms are held together by ________ force.
Electromagnetic
Classifying atoms: depends on protons.
Element
Classifying atoms: depends on total number of nucleons.
Isotopes
Classifying atoms: excess or depletion of electrons compared to ordinary state.
Ion
Number of protons
Atomic number
Number of protons and neutrons
Atomic mass number
States of matter: defined shape, defined volume.
Solid
States of matter: undefined shape, defined volume.
Liquid
States of matter: undefined shape, undefined volume, compressible.
Gas
States of matter: ionized gas, most common state of matter in the universe. (Hint: example: stars.)
Plasma
A spectrum of all colors. Can be produced by reflecting or emitting light.
Continuous spectrum
Colored lines produced by quantized energy released from storage in an atom or molecule. Used to identify elements and compounds.
Emission lines
Lines of absorption in a continuous spectrum that result from the light going through a semi-opaque object.
Absorption lines
Each element has a different ________.
Spectrum
Emission and absorption lines are produced in molecules by ________ and ________.
Rotation; vibration
Continuous spectrum of light emitted by an object as a result of the temperature of the object.
Blackbody/Thermal radiation
Stefan-Boltzmann Law
Hotter objects emit more light.
Wien’s Law
Hotter objects change colors.
Change in frequency of a wave caused by the relative motion of the wave source and absorber with respect to each other.
Doppler shift
When the wavelength of the light is longer, the light is:
Redshifted
When the wavelength of light is shorter, the light is:
Blueshifted
The Doppler shift can tell us how fast an object is:
Rotating
Acts as a shutter that controls the amount of light going into the optical system.
Pupil
Focuses the light entering the optical system, uses refraction to direct light.
Lens
Detects photons entering the optical system.
Retina
Transport photon information
Optical nerve
The process by which light can be bent or changed direction.
Refraction
A measure of how well a medium can bend.
Index of refraction
The point at which light rays focus and converge at a single point to form an angle.
Focal point
Not all sources produce parallel rays. The rays focus on this.
Focal plane
How are images created?
From the photons emitted or reflected from the source.
The length of time the shutter is open.
Exposure time
The amount of energy per unit time that is measured or produced.
Power
A detector is broken up into these multiple pieces.
Pixels
How much light a telescope can collect at one time.
Light-collecting area
The smallest angle two dots can be separated/distinguished from each other.
Angular separation
Actual angular separation depends on ________ and ________ _______.
Atmosphere
Process where light waves interact with each other.
Interference
Refracts light to a focal point. Limited by how much a material can refract/bend light.
Refracting telescope
Reflects light off of multiple mirrors to one focal point. More compact and easier to maneuver.
Reflecting telescopes