COT Exam Review Manual Flashcards
The range of range of wavelength in the visible spectrum is:
a. 100 to 400 nanometers
b. 400 to 800 nanometers
c. 450 to 650 nanometers
d. 400 to 800 meters (m)
b. 400 to 800 nanometers
Make sure to pay attention to the units of measurement used as this can trip you up.. option D has m not nm.
Immediately on either side of the visible spectrum are the invisible light segments of:
a. infrared and ultraviolet
b. X-rays and radio waves
c. gamma rays and lasers
d. microwaves and radar
a. infrared and ultraviolet
Infrared light borders the visible color red and ultraviolet light borders the visible color violet. All of the other answers are invisible components of the electromagnetic spectrum, but do not abut red or violet.
Which color has the longest wavelength?
a. red
b. yellow
c. green
d. blue
a. red
Red’s wavelength is 650 nanometers
Geometric optics includes:
a. the origin of light waves and particles
b. the effects of media on the path of light
c. how light travels through the eye
d. physics of the visible light spectrum
b. the effects of media on the path of light
Geometric optics involves the reaction of light as it passes through media (any transparent object) or strikes a surface. Answers a & d refer to physical optics. Physiologic optics defines answer c.
When light bounces back from an object, this is known as:
a. reflection
b. refraction
c. transmission
d. index of refraction
a. reflection
In reflection, the light rays that hit the object or interface between media with different indices of refraction are called:
a. incident rays
b. reflected rays
c. refracted rays
d. transmitted rays
a. incident rays
The light that hits the object or interface is termed incident, those rays that bounce back from the object or interface are called reflected.
In optics, a medium (or media, plural) is:
a. an object that refracts light
b. an object that emits light
c. an object that reflects light
d. an object through which light passes
d. an object through which light passes through
A medium is a transparent object through which light can pass. It is not a light source (ie, does not emit light) it does not necessarily refract light, either.
When light passes through a transparent medium, it may travel straight through (transmission) or its path may be altered. This altering or bending property of a medium is known as:
a. reflection
b. refraction
c. absorption
d. tropism
b. refraction
The quality of a medium to bend light is called refraction. In reflection, the rays are bounced off of the surface. Absorbed light does not pass through a medium. Tropism actually refers to the phenomenon of plants bending toward a light source.
The ray of light that enters a transparent medium is termed:
a. incident ray
b. divergent ray
c. emergent ray
d. parallel ray
a. incident ray
The incident ray is the ray that first strikes and enters a medium. A divergent ray has been refracted outward. The emergent ray is the ray as it exits the medium. A parallel ray is straight.
If light passes through a lens and the rays are spread apart on exiting, this is known as:
a. index of refraction (IR)
b. convergence
c. zero vergence
d. divergence
d. divergence
If light passes through a lens and the rays are bent toward each other on existing, this is known as:
a. IR (Index of refraction)
b. convergence
c. zero convergence
d. divergence
b. convergence
A comparison of the speed of light in air to the speed of light through a substance is:
a. IR (snell’s law)
b. angle of refraction
c. internal reflection
d. optical interference
a. IR (snell’s law)
The IR of a substance is found by dividing the speed of light in the air by the speed of light through the substance. This is also known as Snell’s Law.
The denser the substance, the more slowly light passes through it, and:
a. the lower the IR
b. the higher the IR
c. the more transparent it is
d. the more suitable it is for use as an ophthalmic lens
b. the higher the IR
The IR of crown glass is:
a. 0
b. 1.00
c. 1.33
d. 1.50
d. 1.50
Light traveling through a vacuum is zero, through air is 1.0 and through water is 1.33
Light traveling through a prism will be bent toward the prism’s:
a. apex
b. base
c. center
d. smallest angle
b. base
The image of an object viewed through a prism:
a. is real and shifted toward the base
b. is virtual and shifted toward the base
c. is real and shifted toward the apex
d. is virtual and shifted toward the apex
d. is virtual and shifted toward the apex
A 1.00 diopter prism bends light:
a. 1 centimeter (cm) at a distance of 1 cm from the prism
b. 1 m at a distance of 1 cm from the prism
c. 1 cm at a distance of 1 m from the prism
d. 1 m at a distance of 1 m from the prism
c. 1 cm at a distance of 1 m from the prism
A 2.oo diopter prism displaces an object 1 cm at a distance of:
A. 0.2 m
B. 0.5 m
C. 1.5 m
D. 5.0 cm
B. 0.5 m
The displacement of an object 5 cm at a distance of 1 m would require prism of:
A. 0.5 diopters
B. 1.0 diopters
C. 2.0 diopters
D. 5.0 diopters
D. 5.0 diopters
At a distance of 2 m, a 12 diopter prism would displace an object:
A. 6 cm
B. 2.4 m
C. 24 cm
D. 6 m
C. 24 cm
A spherical lens refracts light:
A. Not at all
B. In one direction only
C. Equally in every direction
D. At 90 degrees from its axis
C. Equally in every direction
A 1.00 diopter spherical lens focuses light at:
A. 1/2 m
B. 1 m
C. 1 cm
D. 1 yard (yd)
B. 1 m
The point at which a lens forms an image (whether real or virtual) is the:
A. Nodal point
B. Conoid of Sturm
C. Focal Length
D. Focal Point
D. Focal Point
All of the following regarding the optical center of a lens is true except:
A. It always coincides with the geometric center of the lens
B. Light rays passing through it are not refracted
C. It also is known as the nodal point
D. It should be centered in line with the patient’s visual axis
A. It always coincides with the geometric center of the lens
The focal length of a lens:
A. Is the distance between the lens and the focal point
B. Is the dioptric power of the lens
C. Is the point where light is focused
D. Is related to the axis of the cylinder
A. Is the distance between the lens and the focal point
Because the focal point of a minus lens is virtual, the focal length of a minus lens:
A. Cannot be calculated
B. Is likewise virtual
C. By contrast, is real
D. Is insignificant
B. Is likewise virtual
Which of the following is the formula for finding focal length?
A. IR = speed of light in air/speed of light in substance
B. P = C/D
C. P = I/F
D. U + P = V
C. P = I/F
What is the focal length of a 5 diopter lens?
A. 5 m
B. 0.5 m
C. 2 m
D. 0.2 m
D. 0.2 m