1. absorption in terms of light and lenses-when a ray of light
enters a lens some of the light will not completely
travel through the lenses.
2. deviation the angle a ray of light is changed from its original-
path
3. diffuse reflection a reflection from a rough surface - the reflection
does not produce a clear image
4. incidence the angle which a ray of light makes with the surface
of a refracting medium
5. reflection the return of light waves from a surface, the produc-
tion of an image
6. refraction the bending of light when going from one medium
into another
7. refraction(angle of) the angle created when a ray of light passes from
one medium into another
8. specular reflection the forming of a clear image when light strikes a
surface
9. why is the pencil red? it reflects red rays back toward the eye and absorbs
all other rays of visible light
10. why is the blacktop black? it does not reflect any rays back toward your eye;
rather, it absorbs them all
11. if a light beam passes through a the green rays are refracted through the lens and
green sunglass lenses, why will the all other color rays are absorbed by the pigments in
exiting light be green? the lens material
,12. when a ray of light travels from air it slows down but does not change direction. it is not
into water - which is denser than air deviated or displaced
- what happens to the ray of light if:
the ray is perpendicular to the sur-
face
13. the ray is not perpendicular to the it slows down and changes direction toward the
surface normal. it is deviated from its original path
14. when a ray of light travels from water it speeds up but does not change direction. it is not
into air- which is rarer than water- deviated or displaced
what happens to the ray of light if:
The ray is perpendicular to the sur-
face?
15. the ray is not perpendicular to the it speeds up and changes direction away from the
surface? normal. it is deviated from its original path
16. what does critical angle mean? a light ray leaving a denser material for a rarer
material that is at an angle to the normal that results
in it traveling parallel to the surface of the material.
if the angle of incidence is greater than the critical
angle the ray will reflect inside the material and will
not exit into the rarer material.
17. if a light ray travels from air to water i=15 r=11 d=? i=r+d 15=11+d d=15-11 d=4
with an angle of incidence of 15 de-
grees and an angle of refraction of 11
degrees, how much was it deviated?
18. if the light ray leaves the water travel- i=20 r-? d=-7 i=r+d 20=r+(-7) r-7=20 r=20+7 r=27
ing into air with an angle of incidence
, of 20 degrees and it is deviated by -7
degrees, what is the angle of refrac-
tion?
19. if a ray of light travels from one ma- i=r+d i=? r=20 d=5 i=r+d i=20+5 i=25 the ray is again
terial to another with an angle of in- entering the lens material.
cidence of 32 and an angle of refrac-
tion of 26, what is the angle of devia-
tion? is the ray travelling into the lens
or exiting from lens?
20. a ray of light travels from one mater i=r+d i=45 r=65 d=? i=r+d 45-65+d d=45-65 d=-20
to another. the angle of incidence is the ray is exiting from the lens material into air or
45 degrees and the angle of refrac- another material which is not as dense
tion is 65 degrees. what is the angle
of deviation? is the ray entering the
lens material or exiting from it?
21. a ray of light is deviated by -10 de- i=r+d i=29 r=? d=-10 29=r-10 r=29+10 r=39 the ray
grees from its path when it passes is exiting the densest material
from one material into another ma-
terial. if it was originally travelling at
an angle of 29 degrees to the normal,
what is its angle of refraction? it is
travelling into the denser material or
is it exiting the denser material?
22. when a ray of light leaves a lens medi- the ray is going from a dense material to air. the an-
um and enters air it is travelling at gle of incidence is going to be less than 36 degrees.
an angle of 36 degrees to the nor-
mal. would the angle of incidence be
greater than 36 degrees, less than
36 degrees or equal to 36 degrees?
, (note: the word medium is used in
place of material. in this context they
mean the same thing. you could use
either term used on a test.)
23. a ray of light enters a diamond from i=r+d i=3 r=? d=2 i=r+d 3=r+2 r=3-2 r=1
air, travelling at an angle of 3 degrees
from the normal to the surface. if it
is deviated from its original path by
2 degrees, what is its angle of refrac-
tion?
24. because the sides of the diamond are i=r+d i=20 r=55 d=? i=r+d 20=55+d d=20-55 d=-35
carefully designed, the ray that en-
tered the diamond close to the nor-
mal might exit the opposite side at
20 degrees away from the normal.
if it is refracted through an angle of
55 degrees, how much has it been
deviated?
25. if a ray of light is deviated by -14 de- i=r+d i=? r=25 d=-14 i=r+d i=25-14 i=11 it went from
grees, and its angle of refraction is 25 slower to faster, or from more dense to less dense
degrees, what was the angle of inci-
dence? did it go from a faster medi-
um to a slower medium, of from a
slower medium to a faster medium?
26. focal power formula: D=1/f, where f is
in meters:
D=39.37/f, where f is in inches. (1 me-
ter=39.37 inches)