Chapter 25 Flashcards
(25 cards)
light is regarded as having a dual nature: light sometimes acts like a ________ and sometimes acts like a ________
wave
particle
a wave that has a wavelength that is less than d emerges from an opening in a ________, this is the assumption of the ray approximation
straight line
a wave that is on the same order of wavelength as it is d results in ________, the waves spread out from the opening in all directions
diffraction
a wave with a wavelength that is much wider than d, the opening, results in ________ that is so great that the opening can be assumed to be a ________
diffraction
point source
________ is reflrection from a smooth surface, in which the reflected rays are ________ to each other
specular reflection
parallel
________ is reflection from a rough surface, in which the reflected rays travel in a variety of directions
diffuse reflection
the angle of reflection is ________ to the angle of incidence
equal
the bending of the ray is called ________
refraction
the path of the light through the refracting surface is ________
reversible
when light refracts into a material where its speed is LOWER, the angle of refraction is ________ than the angle of incidence. the ray bends ________ the normal.
less
towards
when light refracts into a material where its speed is HIGHER, the angle of refraction is ________ than the angle of incidence. the ray bends ________ the normal.
greater
away from
why does the speed change inside a material?
atoms absorbing light, or oscillating and reradiating the light
the ________ and ________ cause the average speed of the light moving through the material to decrease
absorption
radiation
as light travels from one medium to another, its frequency remains ________
constant
for a given material, the index of refraction varies with the ________ of the light passing through the material. The dependence of n on ________ is called ________
wavelength
wavelength
dispersion
the index of refraction for a material generally ________ with increasing wavelength
decreases
violet light (lambda = 400 nm) bends ________ than red light (lambda = 650 nm) when passing into a refracting material
more
consider a ray of light striking a prism… the ray emerges refracted from its original direction of travel by an angle called the ________
angle of deviation
the angle of deviation depends on the ________ and the ________ of the material
apex
index of refraction
since all colors have different angles of deviation, white light will spread out into a spectrum
- violet deviates ________
- red deviates ________
the most
the least
huygen’s principle is a geometric model that allows us to determine the ________ of a wave front from a knowledge of an ________ wave front
position
earlier
a phenomenon called ________ can occur when light is directed from a medium having a given index of refraction toward one having a lower index of refraction
total internal reflection
there is a particular angle of incidence that will result in angle of refraction of ________. This angle of incdence is called the ________
90 degrees
critical angle
for angles of incidence ________ than the critical angle no ray is refracted and the incident beam is ________ reflected at the boundary.
greater
entirely
