Physics Exam 3 Flashcards
convex spherical mirror
has a reflecting surface that bulges outward
-reflects rays that are parallel to its principal axis so they diverge
spherical mirror
has a spherical reflecting surface
concave spherical mirror
has a hollowed reflecting surface
-reflects rays that are parallel to its principal axis so that they pass through a point known as the focal point
focal length
distance from the surface of the mirror to the focal point
paraxial rays
rays that are rays that are close to the principal axis of a mirror
spherical aberration
blurred effect caused from rays that are farther from the axis
mirror equation
relates the object distance, image distance, and focal length
*focal length is positive for a concave mirror and negative for convex
human eye
forms a real, but inverted, image on the retina
camera
forms a real, but inverted, image on light-sensitive material
focusing the eye
- focused by the ciliary muscles, which change the shape of the lens
- process is known as accommodation
focusing a camera
- focused by moving the lens closer to or farther away from the light-sensitive material
- shape of the lens is unchanged
near point
- the closest distance to which the eye can focus
- typical value is 25cm
far point
- the greatest distance at which the eye can focus
- far point is infinity
f-number
relates the diameter of the aperture to the focal length
nearsightedness
a condition in which clear vision is restricted to a region relativly close to the eye
- the far poinr is nor infinity
- can be corrected with diverging lenses placed in front of eyes
farsightedness
- person can see clearly only at a relatively large distance from the eye
- the person’s near point is much farther from the eye
- can be corrected by placing converging lenses in front of the eyes
refractive power of a lens
refers to its ability to bend light and is measured in diopters
- the greater the magnitude of the refractive power, the more strongly the lens bends light
- a positive refractive power indicates a converging lens
- a negative refractive power indicates a diverging lens
magnifying glass
- a converging lens
- works by allowing an object to be viewed at a distance less than the near-point distance
compound microscope
uses two lenses in combination to produce a magnified image
- an objective 2. eyepiece
- object to be viewed is placed just outside the focal length of the objective
- image formed by the objective lens is viewed by the eyepiece giving additional magnification
telescope
provides magnified views of distant objects using two lenses
- the objective lens focuses the incoming light at its focal point
- the eyepiece magnifies the image formed by the object
length of a telescope
the sum of the focal lengths of its two lenses
reflecting telescope
uses a mirror in pace of an objective lens
-the largest telescopes are reflectors
lens aberration
any deviation of a lens from ideal behavior
spherical aberration
parallel rays of light passing through a lens fail to go through a single focal point
-its related to the shape of a lens
chromatic aberration
results from dispersion withon a refracting material
-causes different colors to focus at different points
superposition
the addition of two or more waves to give a resultant wave
superposed waves
the result may be a wave of greater amplitude (constructive interference)
-or reduced ampliture (destructive interference)
monochromatic light
consists of waves with a single frequency and a single color
coherent light
light waves that maintain a constant phase relationship with one another
incoherent light
light waves in which the relative phases vary randomly with time
Young’s two slit experiment
light passing through two slits forms bright and dark interference “fringes”
no phase change
occurs when light is reflected from a region with a lower index of refraction
180degree phase change
occurs when light reflects from a region with a higher index of refraction, or from a solid surface
air wedge
formed when two plates of glass that touch on one end and have a small separation on the other end
newton’s rings
when a piece of glass with a spherical cross section is placed on a flat sheet of glass, the resulting interference fringes form a set of concentric circles known as newton’s rings
thin films
can produce colors in reflected light by eliminating other colors with destructive interference
diffraction
phenomenon when a wave encounters an obstacle, or passes through an opening, it changes direction
single-slit diffraction
when monochromatic light passes through a single-slit of width, it forms a diffraction pattern of alternating bright and dark fringes
bright fringes
located approximately halfway between successive dark fringes
-the central bright fringe is approximately twice as wide as the other bright fringes
resolution
refers to the ability of a visual system, like the eye or a camera, to distinguish closely spaced objects
Rayleigh’s criterion (qualitiative statement)
states the two objects become blurred together when the first dark fringe on one object’s diffraction pattern passes through the centere of the other object’s diffraction pattern
Rayleight’s criterion (quantitative statement)
states that if the angular separation between two objects is less than a certain minimum, they will appear to be a single object
diffracting grating
a large number of slits through which a beam of light can pass
-characterized by the number of lines or slits they have per centimeter (N)
reflection gratings
diffraction gratings can also be constructed from a reflecting surface with a large number of reflecting lines, like a CD or butterfly wing
irridescence
when white light shines on a reflecting grating, different colors in the light are reflecte at different angles
-the color effects produce in this way are referred to as irridescence
idedal blackbody
an object that absorbs all the light incident on it
-distribution of energy as a function of frequency within a blackbody is independent of the material from which the blackbody is made and depends only on the temperature
Planck’s Quantum Hypothesis
Planck hypothesized that the energy in a blackbody at a frequency f must be an integer multiple of the consant h=6.63x10^-34
photons
- light is composed of particle-like photons
- carry energy in discrete amounts
- have zero rest mass
- nonzero momentum
- collide with other particles
energy of a photon
depends on its frequency
photoelectric effect
occurs when photons of light eject electrons from the surface of a metal
work function
the minimum energy required to eject an electron from a particular metal
cutoff frequency
if the frequency of the photon is greater than the frequency, the ejected electron has a finite kinetic energy
compton effect
if a pohoton undergoes a collision with an electron and scatters into a new direction its new wavelength is fiven by the compton shift formula
de Broglie hypothesis
since light displays particle-like behavior, praticles display wavelike behavior.
-hypothesized that particles have wavelengths
wave-particle duality
light and matter display both wavelike and particle-like properties
quantum tunneling
particles can pass through regions of space that would be forbidden to a classical particle
atoms
smallest unit of a given element
-if an atom is broken down into smaller pieces, it loses the properties that characterized the element
Thomson Model
aka plum pudding
-an atom is imagined to be like a positively charged pudding with negatively charged electrons scattered throughout
rutherfold model
aka a miniature solor system
- an atom is somewhat like an atomic-scal solor system: mostly empty space, with most of its mass concentrated in the nucleus
- electrons thought to orbit the nucleus
spectrum of hydrogen
excited atoms of hydrogen in a low-pressure gas give off light of specific wavelengths
bohr’ model of the hydrogen atom
assumes
- electrons move in circular orbits about the nucleus
- allowed orbits must have an angular momentum
- electrons in allowed orbits do not give off electromagnetic radiation
- radiation is emitted only when electrons jump from one orbit to another
multielectron atoms and the periodic table
as electrons are added to atoms, the properties of the atoms change in a regular and predictable way
multielectron atoms
energy levels in a multielectron atom depend on n and l.
-the energy increases with increasing n for fixedl, and with increasing l for fixed n
shells and subshells
electrons with the same value of n are said to be in the same shell
-electrons in a given shell with the same value of l are said to be in the same subshell
the Pauli exclusion principle
states that only a single electron may have a particular set of quantum number
-means that it is not possible for all the elextrons in a multielectron atom to occupy the lowest energy level
electronic configurations
the arrangement of electrons is indicated by the electronic configuration
the periodic table
as electrons fill subshells of progressively higher energy, they produce the elements of the periodic table.
-atoms with the same configuration of outermost electrons generally have similar chemical properties
atomic radiation
atoms can give off radiation ranging from x-rays to visible light to infrared rays
xrays
given off when an electron in an inner shell is knocked out of the atom, and an electron from an outer shell drops down to take its place
lasers
a device that produces light amplification by he stimulated emission of radiation
fluorescence and phosphorescence
when an electron in an atom is excited to a high energy level, it may return to the ground state through a series of lower-energy jumps
-these jumps give off radiation of longer wavelength than the radiation that caused the original excitation
astigmatism
an irregular curvature of the cornea
