ABO OPTICAL EXAM
What is the minimum safety thickness?
A) 3.00mm
B) 2.2mm
C) 1.5mm
D) 4.25mm - A) 3.00mm
A lens reads +4.25 in the vertometer. If the ocular curve is -4.00 what is the front base curve?
A) +0.25D
B)+4.00D
C)+6.25D
D)+8.25D - D)+8.25
Anti reflective coating of a lens is based on the principle of:
A) diffraction
B) reflection
C) interference
D) reflection and interference - D) reflection and interference
Concave mirror:
A) can focus parallel incident rays to form a real image
B) can focus parallel incident Rays to form a virtual image
C) always produce inverted images of real objects
D) produces virtual images smaller than the real object. - A) can focus parallel incident rays to
form a real image
Crown glass index - 1.523
, Define Phoria - A TENDENCY to cross (not cosmetic)
Define Tropia - An actual "crossing" very noticeable.
Light falling on the front surface of a spectacle lens is:
A) partially reflected, partially absorbed and the remainder refracted
B) partially reflected and the remainder refracted
C) partially absorbed and the remainder refracted
D) totally refracted - A) partially reflected, partially absorbed and the remainder refracted
Minus Lenses Can Be
A) Convex
B) Concave
C) Both - B) Concave
(minus lenses can be equiconcave, flat concave, double concave/bioconcave or meniscus)
Nominal power equation - Dn= D1+D2. (Lens power (Dn) equals the power of the front surface
(D1) and the power of the back surface (D2) of the lens)
Plus Lenses can be
A) Convex
B) Concave
C) Both - A) Convex
(plus lenses can be equiconvex, Flat convex, Double covex/biconvex or Meniscus)
Reflection is reduced by depositing a layer of magnesium fluoride on the lens surface. It has a thickness
of:
A) 1/2 the wave length of white light
B) 1/4 the wave length of white light
What is the minimum safety thickness?
A) 3.00mm
B) 2.2mm
C) 1.5mm
D) 4.25mm - A) 3.00mm
A lens reads +4.25 in the vertometer. If the ocular curve is -4.00 what is the front base curve?
A) +0.25D
B)+4.00D
C)+6.25D
D)+8.25D - D)+8.25
Anti reflective coating of a lens is based on the principle of:
A) diffraction
B) reflection
C) interference
D) reflection and interference - D) reflection and interference
Concave mirror:
A) can focus parallel incident rays to form a real image
B) can focus parallel incident Rays to form a virtual image
C) always produce inverted images of real objects
D) produces virtual images smaller than the real object. - A) can focus parallel incident rays to
form a real image
Crown glass index - 1.523
, Define Phoria - A TENDENCY to cross (not cosmetic)
Define Tropia - An actual "crossing" very noticeable.
Light falling on the front surface of a spectacle lens is:
A) partially reflected, partially absorbed and the remainder refracted
B) partially reflected and the remainder refracted
C) partially absorbed and the remainder refracted
D) totally refracted - A) partially reflected, partially absorbed and the remainder refracted
Minus Lenses Can Be
A) Convex
B) Concave
C) Both - B) Concave
(minus lenses can be equiconcave, flat concave, double concave/bioconcave or meniscus)
Nominal power equation - Dn= D1+D2. (Lens power (Dn) equals the power of the front surface
(D1) and the power of the back surface (D2) of the lens)
Plus Lenses can be
A) Convex
B) Concave
C) Both - A) Convex
(plus lenses can be equiconvex, Flat convex, Double covex/biconvex or Meniscus)
Reflection is reduced by depositing a layer of magnesium fluoride on the lens surface. It has a thickness
of:
A) 1/2 the wave length of white light
B) 1/4 the wave length of white light
