NAO VOLUME 2 EXAM QUESTIONS
AND ANSWERS ALL CORRECT
A group of rays emitted from a small single point on a light source, it requires a large
hole in the second screen? - Answer- Pencil
We use the acronym ROY G BIV to help remember the order of colors. It list colors
from? - Answer- Long wavelengths to short wavelengths
Which wavelength of ultra-violet radiation is absorbed by the ozone layer? - Answer-
UV-C
The bending or redirection of a light wave when it passes a barrier without changing the
medium in which it is traveling is called? - Answer- Diffraction
When a light ray travels from one transparent medium to another, it changes direction.
This bending of light, which results from the differences in density of different
transparent materials is called? - Answer- Refraction
When a ray of light travels from one material to another, if its direction of travel is
perpendicular or normal to the interface or junction between the materials it will? -
Answer- change speed by not direction
When a ray of light travels from a less dense (faster) material to a more dense (slower)
material at an angle to the normal it will? - Answer- bend toward the normal
What do you look for when you are trying to determine which lens material would be
thinner? - Answer- highest index of refraction
How are glass lenses hardened? - Answer- heating treating is done in two or three
minutes in a small furnace and chemical treating is done by immersing lenses in molten
salt
How long does the FDA require you keep a patients file? - Answer- 3 years
The Federal Trade Commission established Eyeglasses I in 1978 and Eyeglasses II in
1989. What is the difference? - Answer- Eyeglasses I is the prescription release rule
and list minimum information to be included in the RX. Eyeglasses II no longer list
minimum information needed to make spectacle RX
, When a ray of light travels from a more dense (slower) material to a less dense (faster)
material at an angle to the normal it will? - Answer- bend away from the normal
If light travels through a liquid at 140,000 miles per second, what is the index of liquid? -
Answer- 1.32
Absorption - Answer- in terms of light and lens- when a ray of light enters a lens some
of the light will not completely travel through the lens
Deviation (Angle of) - Answer- the angle a ray of light is changed from its original path
Diffuse Relection - Answer- a reflection from a rough surface- the reflection does not
produce a clear image
Incidence (Angle of) - Answer- the angle which a ray of light makes the surface of a
refracting medium
Reflection - Answer- the return of light waves from a surface the production of an image
Refraction - Answer- the bending of light when going from one medium into another
Refraction (Angle of) - Answer- the angle created when a ray of light passes from one
medium into another
Specular Reflection - Answer- the forming of a clear image when light strikes a surface
Why is a red pencil red? - Answer- It reflects red rays back toward the eye and absorbs
all the other rays of visible light
Why is the blacktop black? - Answer- It does not reflect any rays back toward your eye;
rather it absorbs them all
If a light beam passes through a green sunglasses lens, why will the exciting light be
green? - Answer- The green rays are refracted through the lens and all other color rays
are absorbed by the pigments in the lens material
When a ray of light travels from air into water (which is denser than air) what happens to
the ray of light if the ray is perpendicular to the surface? - Answer- If the ray is
perpendicular to the surface it slows down but does not change direction; it is not
deviated or displaced
When a ray of light travels from air into water (which is denser than air) what happens to
the ray of light if the ray is not perpendicular to the surface? - Answer- If the ray is not
perpendicular to the surface it slows down and changes direction toward the normal; it
is deviated from its original path
AND ANSWERS ALL CORRECT
A group of rays emitted from a small single point on a light source, it requires a large
hole in the second screen? - Answer- Pencil
We use the acronym ROY G BIV to help remember the order of colors. It list colors
from? - Answer- Long wavelengths to short wavelengths
Which wavelength of ultra-violet radiation is absorbed by the ozone layer? - Answer-
UV-C
The bending or redirection of a light wave when it passes a barrier without changing the
medium in which it is traveling is called? - Answer- Diffraction
When a light ray travels from one transparent medium to another, it changes direction.
This bending of light, which results from the differences in density of different
transparent materials is called? - Answer- Refraction
When a ray of light travels from one material to another, if its direction of travel is
perpendicular or normal to the interface or junction between the materials it will? -
Answer- change speed by not direction
When a ray of light travels from a less dense (faster) material to a more dense (slower)
material at an angle to the normal it will? - Answer- bend toward the normal
What do you look for when you are trying to determine which lens material would be
thinner? - Answer- highest index of refraction
How are glass lenses hardened? - Answer- heating treating is done in two or three
minutes in a small furnace and chemical treating is done by immersing lenses in molten
salt
How long does the FDA require you keep a patients file? - Answer- 3 years
The Federal Trade Commission established Eyeglasses I in 1978 and Eyeglasses II in
1989. What is the difference? - Answer- Eyeglasses I is the prescription release rule
and list minimum information to be included in the RX. Eyeglasses II no longer list
minimum information needed to make spectacle RX
, When a ray of light travels from a more dense (slower) material to a less dense (faster)
material at an angle to the normal it will? - Answer- bend away from the normal
If light travels through a liquid at 140,000 miles per second, what is the index of liquid? -
Answer- 1.32
Absorption - Answer- in terms of light and lens- when a ray of light enters a lens some
of the light will not completely travel through the lens
Deviation (Angle of) - Answer- the angle a ray of light is changed from its original path
Diffuse Relection - Answer- a reflection from a rough surface- the reflection does not
produce a clear image
Incidence (Angle of) - Answer- the angle which a ray of light makes the surface of a
refracting medium
Reflection - Answer- the return of light waves from a surface the production of an image
Refraction - Answer- the bending of light when going from one medium into another
Refraction (Angle of) - Answer- the angle created when a ray of light passes from one
medium into another
Specular Reflection - Answer- the forming of a clear image when light strikes a surface
Why is a red pencil red? - Answer- It reflects red rays back toward the eye and absorbs
all the other rays of visible light
Why is the blacktop black? - Answer- It does not reflect any rays back toward your eye;
rather it absorbs them all
If a light beam passes through a green sunglasses lens, why will the exciting light be
green? - Answer- The green rays are refracted through the lens and all other color rays
are absorbed by the pigments in the lens material
When a ray of light travels from air into water (which is denser than air) what happens to
the ray of light if the ray is perpendicular to the surface? - Answer- If the ray is
perpendicular to the surface it slows down but does not change direction; it is not
deviated or displaced
When a ray of light travels from air into water (which is denser than air) what happens to
the ray of light if the ray is not perpendicular to the surface? - Answer- If the ray is not
perpendicular to the surface it slows down and changes direction toward the normal; it
is deviated from its original path
