NAO EXAM QUESTIONS AND
ANSWERS
Define Incident Ray - Answer- a ray of light that strikes a surface
Angle of Incidence - Answer- the angle between the incident ray and the normal
Angle of Refraction - Answer- the angle between the refracted ray and the normal
Define Aphakia - Answer- absence of a lens
Define presbyopia - Answer- farsightedness caused by loss of elasticity of the lens of
the eye, occurring typically in middle and old age.
What kind of lens corrects myopia? - Answer- concave lens
A concave surface has a _____ value. - Answer- Negative
Define myopia - Answer- nearsightedness
A convex surface has a ______ power. - Answer- Positive
Define hyperopia - Answer- farsightedness
The power of a lens is measured in.... - Answer- diopters
Define astigmatism - Answer- blurred vision due to unequal curvatures of the lens or
cornea
Formula for Metric System - Answer- 1m = 10dm = 100cm = 1000mm
What is one-billionth of a meter? - Answer- nanometer
Visible light ranges from _____ nanometers. - Answer- 400 - 700 nanometers
Which color has the longest wavelength, travels the fastest, bends the least, and has
the least energy? - Answer- Red
ANSWERS
Define Incident Ray - Answer- a ray of light that strikes a surface
Angle of Incidence - Answer- the angle between the incident ray and the normal
Angle of Refraction - Answer- the angle between the refracted ray and the normal
Define Aphakia - Answer- absence of a lens
Define presbyopia - Answer- farsightedness caused by loss of elasticity of the lens of
the eye, occurring typically in middle and old age.
What kind of lens corrects myopia? - Answer- concave lens
A concave surface has a _____ value. - Answer- Negative
Define myopia - Answer- nearsightedness
A convex surface has a ______ power. - Answer- Positive
Define hyperopia - Answer- farsightedness
The power of a lens is measured in.... - Answer- diopters
Define astigmatism - Answer- blurred vision due to unequal curvatures of the lens or
cornea
Formula for Metric System - Answer- 1m = 10dm = 100cm = 1000mm
What is one-billionth of a meter? - Answer- nanometer
Visible light ranges from _____ nanometers. - Answer- 400 - 700 nanometers
Which color has the longest wavelength, travels the fastest, bends the least, and has
the least energy? - Answer- Red
