COT EXAM QUESTIONS AND ANSWERS.
VERIFIED 2026.
The range of wavelengths in the visible spectrum is? - ANS 400 - 800 nanometers
Immediately on either side of the visible spectrum are the invisible light segments of? -
ANS Infrared & ultraviolet
Which color has the longest wavelength? - ANS Red
Geometric optics includes? - ANS The effects of media on the path of light
When light bounces back from an object, this is known as? - ANS Reflection
In reflection, the light rays that hit the object or interface between media with different indices
of refraction are called? - ANS Incident rays
In optics, a medium (or media, plural) is: - ANS An object that reflects light
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? -
ANS Refraction
1 @COPYRIGHT 2025/2026 ALLRIGHTS RESERVED.
,The ray of light that enters a transparent medium is termed? - ANS Incident ray
If light passes through a lens and the rays are spread apart on exiting, this is known as? -
ANS Divergence
If light passes through a lens and the rays are spread toward each other on exiting, this is known
as? - ANS Convergence
A comparison of the speed of light in air to the speed of light through substance is? - ANS IR
(Snell's Law)
The denser the substance, the more slowly light passes through it and the what? - ANS The
higher the IR
The IR of crown glass is? - ANS 1.50
Light traveling through a prism will be bent toward the prisms what? - ANS Base
The image of an object viewed through a prism Is what? - ANS Virtual and shifted toward the
apex
A 1.00 diopter prism bends light? - ANS 1 cm at a distance of 1m from the prism
A 2.00 diopter prism displaces an object 1cm at a distance of what? - ANS 05 m
2 @COPYRIGHT 2025/2026 ALLRIGHTS RESERVED.
,The displacement of an object 5cm at a distance of 1m would require prism of what? -
ANS 5.0 diopters
At a distance of 2m, a 12 diopter prism would displace an object how far? - ANS 24cm
A spherical lens refracts light? - ANS Equally in every direction
A 1.00 diopter spherical lens focuses light at? - ANS 1meter
The point at which a lens forms an image (whether real or virtual is the what? - ANS focal
point
True of false, regarding the optical center of a lens it always coincides with the geometric center
of the lens? - ANS False
The focal length of a lens is what? - ANS 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 is what? -
ANS Likewise virtual
What is the formula for finding the focal length? - ANS P = 1/F
What is the focal length of a 5 diopter lens? - ANS 0.2 m
A lens has a focal length of 33cm what is its dioptic power? - ANS 3 diopters
3 @COPYRIGHT 2025/2026 ALLRIGHTS RESERVED.
, Name 3 characteristics of a cylindrical lens? - ANS 1. They are used to correct astigmatism
2. They have power in one axis, but no power in the axis 90 degrees away
3. They focus light in a line
The direction of the line of light as focused by a plus power cylindrical lens is what? -
ANS Aligned with the axis
Light passing through a cylindrical lens is focused in 2 lines perpendicular to each other &
separated by an area known as what? - ANS Sturm's interval
The light rays in the Sturm's interval are projected in the shape of a what? - ANS cone
Within the Conoid of Sturm the area where the image would be most clearly focused is? -
ANS The circle of lease confusion
An optical cross is a means of what? - ANS Indicating the dioptic power of a lens
The ocular media consists of? - ANS The tear film, cornea, humors & lens
Which ocular structure has the highest refractive power? - ANS Cornea
The primary goal of the eye's components is to what? - ANS Focus incoming light onto the
retina
Images pass through the optic nerve & thence to the what? - ANS Chiasm, optic tract, lateral
geniculate body, & optical cortex
4 @COPYRIGHT 2025/2026 ALLRIGHTS RESERVED.
VERIFIED 2026.
The range of wavelengths in the visible spectrum is? - ANS 400 - 800 nanometers
Immediately on either side of the visible spectrum are the invisible light segments of? -
ANS Infrared & ultraviolet
Which color has the longest wavelength? - ANS Red
Geometric optics includes? - ANS The effects of media on the path of light
When light bounces back from an object, this is known as? - ANS Reflection
In reflection, the light rays that hit the object or interface between media with different indices
of refraction are called? - ANS Incident rays
In optics, a medium (or media, plural) is: - ANS An object that reflects light
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? -
ANS Refraction
1 @COPYRIGHT 2025/2026 ALLRIGHTS RESERVED.
,The ray of light that enters a transparent medium is termed? - ANS Incident ray
If light passes through a lens and the rays are spread apart on exiting, this is known as? -
ANS Divergence
If light passes through a lens and the rays are spread toward each other on exiting, this is known
as? - ANS Convergence
A comparison of the speed of light in air to the speed of light through substance is? - ANS IR
(Snell's Law)
The denser the substance, the more slowly light passes through it and the what? - ANS The
higher the IR
The IR of crown glass is? - ANS 1.50
Light traveling through a prism will be bent toward the prisms what? - ANS Base
The image of an object viewed through a prism Is what? - ANS Virtual and shifted toward the
apex
A 1.00 diopter prism bends light? - ANS 1 cm at a distance of 1m from the prism
A 2.00 diopter prism displaces an object 1cm at a distance of what? - ANS 05 m
2 @COPYRIGHT 2025/2026 ALLRIGHTS RESERVED.
,The displacement of an object 5cm at a distance of 1m would require prism of what? -
ANS 5.0 diopters
At a distance of 2m, a 12 diopter prism would displace an object how far? - ANS 24cm
A spherical lens refracts light? - ANS Equally in every direction
A 1.00 diopter spherical lens focuses light at? - ANS 1meter
The point at which a lens forms an image (whether real or virtual is the what? - ANS focal
point
True of false, regarding the optical center of a lens it always coincides with the geometric center
of the lens? - ANS False
The focal length of a lens is what? - ANS 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 is what? -
ANS Likewise virtual
What is the formula for finding the focal length? - ANS P = 1/F
What is the focal length of a 5 diopter lens? - ANS 0.2 m
A lens has a focal length of 33cm what is its dioptic power? - ANS 3 diopters
3 @COPYRIGHT 2025/2026 ALLRIGHTS RESERVED.
, Name 3 characteristics of a cylindrical lens? - ANS 1. They are used to correct astigmatism
2. They have power in one axis, but no power in the axis 90 degrees away
3. They focus light in a line
The direction of the line of light as focused by a plus power cylindrical lens is what? -
ANS Aligned with the axis
Light passing through a cylindrical lens is focused in 2 lines perpendicular to each other &
separated by an area known as what? - ANS Sturm's interval
The light rays in the Sturm's interval are projected in the shape of a what? - ANS cone
Within the Conoid of Sturm the area where the image would be most clearly focused is? -
ANS The circle of lease confusion
An optical cross is a means of what? - ANS Indicating the dioptic power of a lens
The ocular media consists of? - ANS The tear film, cornea, humors & lens
Which ocular structure has the highest refractive power? - ANS Cornea
The primary goal of the eye's components is to what? - ANS Focus incoming light onto the
retina
Images pass through the optic nerve & thence to the what? - ANS Chiasm, optic tract, lateral
geniculate body, & optical cortex
4 @COPYRIGHT 2025/2026 ALLRIGHTS RESERVED.
