Physics: Waves Part 2
How is light reflected from a convex spherical mirror?
incoming rays diverge after reflection as though they are coming from some point behind the mirror which result in a virtual image and image distance is always negative with a negative focal length.
the difference in frequencies and wavelengths also distinguish visible light from _____________ electromagnetic radiations
invisible
What technique can you use to find the location of an image formed by a lens
ray diagrams for thin-lens systems
when light is reflected at a certain angle from a surface, the ________ _________ is completely polarized parallel to reflecting surface
reflected light
What happens when light travels from a medium of a smaller refractive index to one of a higher refractive index?
the light is bent towards the normal
order number
the number assigned to interference fringes with respect to central bright fringes
dispersion
the process of separating polychromatic light into its component wavelengths
index of refraction
the ratio of speed of light in a vacuum to the speed of light in a given transparent medium n = c/v
What does an image formed by a converging lens look like?
the refraction causes the light to bend towards the normal (see textbook pg. 497)
paraxial rays
those light rays that are very near the principal axis of the mirror
_______________ ____________ ____________ occurs only when light moves along a path from a medium with higher index of refraction to a medium with lower index of refraction
total internal reflection
light from a typical source consists of waves that have electric fields oscillating in random directions is said to be ________.
unpolarized
for calculations in the books, light traveling would be what?
3.00 x 10^8 m/s
what is the equation for wave speed in relation to light?
c = f (wavelength)
in ______________ __________ _____________ theory, light is considered to be a wave composed of oscillating electric and magnetic fields. these fields are perpendicular to the direction in which the wave moves therefore, electromagnetic waves are transverse wave. the electric and magnetic fields are also at right angles to each other.
classical electromagnetic wave
What is a laser?
a device that produces coherent light at a single wavelength
concave spherical mirror
a mirror whose reflecting surface is a segment of the inside of sphere
convex spherical mirror
a mirror whose reflecting surface is an outward-curved segment of a sphere
lens
a transparent object that refracts light rays such that converge or diverge to create an image
electromagnetic wave
a wave that consists of oscillating electric and magnetic fields, which radiate outward from the source at the speed of light
all laser have the same common features in which all substance called _______________ __________ to which energy is added to produce coherent light
active medium
linear polarization
an alignment of electromagnetic waves in such a way that the vibrations of the electric fields in each of the waves are parallel to each other
real image
an image formed when rays of light actually pass through a point on the image
a light ray wavelength 589 nm (produced by a sodium lamp) traveling through air strikes a smooth, flat slab of crown glass at an angle of 30.0 to the normal. find the angle of refraction
angle 1 = 30.0 n (sub) i = 1.00 n (sub) r = 1.52 angle of refraction = ? angle of refraction = sin^-1 [ ni/nr (sin (angle i ) ] = sin ^-1 [1.00 /1.52 (sin 30.0)] angle of refraction = 19.2
if a straight line is drawn perpendicular to the reflecting surface at the incoming rays strikes the surface, the __________ _____ _____________ and __________ ____________ __________ can be defined with respect to the line
angle of incidence and angle of reflection
electromagnetic waves vary depending on frequency and wavelength because in visible light these differences account for different ________.
colors
How is light reflected from a concave spherical mirror?
concave mirrors can produce both real and virtual images when objects move towards a concave spherical mirror its image changes and light ray converge very near the focal point F of the mirror and form an image there. for objects at a finite distance greater than the radius of curvature
waves must have a ________ _____ ______ for interference to be observed
constant phase difference
for light, the result of ______________ ____________ is light that is brighter than the light from the contributing waves.
constructive interference
the distance between the two slits is 0.030 mm. the second order bright fringe (m =2) is measured on the viewing screen at an angle of 2.15 degrees from the central maximum. determine the wavelength of the light
d = 3.0 x 10^-5 m m = 2 sin = 2.15 degrees wavelength = ? d sin= m wavelength wavelength = d sin/m wavelength = (3.0 x 10^-5 m) (sin 2.15) / 2 5.5 x 10^2 nm
that the luminous flux divided by the are of a surface called _______ decreases as the radius squared when you move away from a light source
illuminance
the brightness (intensity) of the laser light can be made much greater than that of _____________ light
incoherent
the condition for interference change with each phase change and therefore no single interference pattern is observed this type is said to be _______
incoherent
__________ is an alternative approach is to use a mirror that is not a segment of sphere but sill focuses light rays in manner that is not a small spherical concave mirror
parabolic mirror
parabolic mirrors are segments of a _______________ whose inner surface is reflecting. all rays parallel to the principal axis converge at the focal point regardless of where on the mirror's surface the rays reflect
paraboloid
if the crest of one overlaps the crest of another wave, the two have a ________ ________ of 0 degrees and are said to be in phase
phase difference
wavelet
point source produces a circular or spherical secondary wave
chromatic aberration
the focusing of different colors of light at different distances behind a lens
an upright orientation of image with respect to object has what sign of magnification and what type does it apply to?
+ and virtual image
an inverted orientation of image with respect to object what is sign of magnification and what does it apply to?
- and real image
if the crest of one wave overlaps the trough of the other wave, the two have a phase difference of _________ degrees and said to be out of phase
180
________ ___________ can be used to drive the properties of any wave including light that interacts with matter, but the same results cam be obtained by treating the propagating wave as a straight line perpendicular to the wave front. this line is called a ray and simplification is called the ray approximation
Huygen's principle
how do draw ray diagrams for lenses
1. parallel ray from object to lens is parallel to principal axis from converging lens to image passes through focal point, F for diverging lend to image directed away from focal point, F 2. central ray from object to lens is to the center of the lens from converging lens to image is from the center of the lens and from diverging lend to image is from the center of the lens 3. focal ray from object to lens is passes through focal point, F from converging lens to image parallel to principal axis from diverging lens to image is parallel to principal axis
What are the 3 steps in drawing ray diagrams?
1. parallel to principal axis through focal point F 2. through focal point F parallel to principal axis 3. through center of curvature C back along itself through C
What is the mirror equation?
1/p + 1/q = 2/R
what is light?
Light is electromagnetic radiation that consists of oscillating electric and magnetic fields with different wavelengths
what is the equation for magnification?
M = h' /h = - q/p
What is the relationship between frequency, wavelength, and the speed of light?
The frequency times the wavelength of electromagnetic radiation is equal to c, the speed of light
equation for destructive interference
d sin^-1 = +- (m + 1/2) wavelength m = 0,1,2,3,....
equation for constructive interference
d sin^-1 = +-m wavelength m = 0,1,2,3,....
for light. the result of _________ ________ is dimmer light or dark spots
destructive interference
when light is reflected of a textured surface it goes in different directions called _____ _______
diffuse reflection
ray diagrams
drawings that use simple geometry to locate an image formed by a mirror
laser transform ________ into coherent light
energy
the AM radio band extends from 5.4 x 10^5 Hz to 1.7 x 10^6 Hz. what are the longest and shortest wavelengths in this frequency range?
f1 = 5.4 x 10^5 Hz f2 = 1.7 x 10^6 Hz c = 3.00 x 10^8 m/s wavelength 1 = ? wavelength 2 = ? c = f (wavelength) wavelength = c/f wavelength 1 = 3.00 x 10^8 m/s / 5.4 x 10^5 Hz wavelength 1 = 5.6 x 10^2 m wavelength 2 = 3.00 x 10^8 m/s / 1.7 x 10^6 Hz = wavelength = 1.8 x 10^2 m
for a spherical mirror, the ____ _____ is equal to half the radius of curvature of the mirror
focal length
because the light rays are reversible, the reflected rays from a light source at the _____ ______ will emerge parallel to each other and will not form an image
focal point
luminous flux
is a measure of power output but is weighted to take into account the response of human eye to light
How is light reflected from a flat mirror?
it is reflected in one direction only which is called specular reflection. rays appear to come from a location on the other side of the mirror. the object and image distances are equal the image forms by rays appear to come from the image point behind the mirror called virtual image
wave fronts
line of particles forms consist of a line of particles. another line of particles forms a low-lying trough in the wave and still another line of particles forms the crest of the second wave
electric field of unpolarized light waves can be treated as combinations of vertical and horizontal electric field oscillations; there are certain processes that separate waves with the electric field oscillations in the vertical direction from those in the horizontal direction, producing a beam of light with electric field waves oriented in the same direction is said to be __________ _______________
linear polarization
the rate at which light emitted from a source is called ____________ _______ and measured in lumens (lm)
luminous flux
in addition, the light produced by a laser is _______________ so all waves have exactly the same wavelength
monochromatic
find the critical angle for a water-air boundary if the index of refraction of water is 1.333
n(sub)i = 1.333 n(sub)r= 1.000 critical angle =? sin (critical angle) = n(sub)r/n(sub)i critical angle = sin ^-1 (1.00/1.333) = 48.6 degree
illuminance decreases as the square of the distance from the source because it is easy to see something _________ to the light source than farther away.
nearer
What does Snell's law state?
ni sin (angle sign) I = nr sin (angle of refraction) o
only light waves that are linearly polarized with _________ to the transmission axis of the polarizing substance can pass freely through the substance
respect
all electromagnetic waves move at the same speed of light because all forms of electromagnetic radiation travel at a ________ ________ _______ in a vacuum.
single high speed
the active medium can be a _______, ________, or _______
solid, liquid, or gas
in ____________ ____________ light rays and real spherical mirrors certain rays do not exactly intersect at the image point
spherical aberration
for two waves to produce a ______________ ___________ pattern the phase of the individual waves must remain unchanged relative to one another
stable interference
when light of a certain wavelength is applied to excited atoms, the atoms can induce to release light waves that have the same properties; after one atom spontaneously releases its energy in the form of a light wave, the initial wave can caused others to energized to release energy as light waves with the same wavelength, phase, and direction as initial wave this process is called ________ __________
stimulated emission
angle of incidence
the angle between a ray that strikes a surface and the line perpendicular to that surface at the point of contact
angle of reflection
the angle formed by the line perpendicular to a surface and the direction in which a reflected ray moves
critical angle
the angle of incidence at which the refracted light makes an 90 degree angle with the normal sin (critical angle) = n(sub)r/n(sub)i for n(sub)i > n (sub)r
refraction
the bending of front waves as front wave passes between two substances in which the speed of wave differs
reflection
the change in direction of an electromagnetic wave at a surface that causes it to move away from the surface
What is total internal reflection?
the complete reflection takes place within a substance when the angle of incidence of light striking the surface boundary is greater than the critical angle
coherence
the correlation between the phases of two or more waves
path difference
the difference in the distance traveled by two beams when they are scattered in the same direction from different points
What is the difference between a real and a virtual image?
virtual image is an image that forms at point from which light rays appear to come but do not actually come for this reason virtual image can never be displayed on a physical surface
the spectrum includes more than visible light because not all light is ________ to the human eye.
visible
_____________ affects the index of refraction because the amount that light bends when entering a different medium depends on the wavelength of the light as well as speed; each color has a different wavelength therefore each color of the spectrum is refracted by a different amount
wavelength
How are light and dark interference patterns formed by light waves?
when wave from a more distant slit must travel wavelength farther than the wave from the nearer slit they are in phase from a constructive interference bright fringes appears; when a wave meets midway between two bright fringes one wave travels half a wavelength farther than the second giving a destructive interference that dark fringes appears
