Optics and Lens Design Concepts, Exams of Nursing

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NAO Volume 2 questions well answered already passed Absorption - correct 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) - correct answer ✔✔the angle a ray of light is changed from its original path Diffuse Reelection - correct answer ✔✔a reflection from a rough surface- the reflection does not produce a clear image Incidence (Angle of) - correct answer ✔✔the angle which a ray of light makes the surface of a refracting medium Reflection - correct answer ✔✔the return of light waves from a surface the production of an image Refraction - correct answer ✔✔the bending of light when going from one medium into another Refraction (Angle of) - correct answer ✔✔the angle created when a ray of light passes from one medium into another Specular Reflection - correct answer ✔✔the forming of a clear image when light strikes a surface Why is a red pencil red? - correct answer ✔✔It reflects red rays back toward the eye and absorbs all the other rays of visible light Why is the blacktop black? - correct 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? - correct 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? - correct 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? - correct 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 When a ray of light travels from water into air ( which is rarer than water) what happens to the ray of light if the ray is perpendicular to the surface? - correct answer ✔✔If the ray is perpendicular to the surface it speeds up but does not change direction; it is not deviated or displaced hen a ray of light travels from water into air ( which is rarer than water) what happens to the ray of light if the ray of light is not perpendicular to the surface? - correct answer ✔✔If the ray is not perpendicular to the surface it speeds up and changes direction away from the normal; it is deviated from its original path What does critical angle mean? - correct answer ✔✔a light ray leaving a denser material is rarer material that is at an angle of normal that results in it traveling parallel to the surface of the material. If the angle of incidence is greater than the critical angle the ray will reflect inside the material and will not exit into the rarer material What are the three things that can happen to a ray of light when it passes through a lens? - correct answer ✔✔absorbed, reflected, refracted What is the difference between a high index lens and a aspheric lens - correct answer ✔✔high index refers to the material of the lens; aspheric refers to the surface design of the lens What is transposition? - correct answer ✔✔is the changing of a precription from plus cylinder to minus cylinder or the other way around A group of rays emitted from a small single point on a light source, it requires a large hole in the second screen? - correct answer ✔✔Pencil We use the acronym ROY G BIV to help remember the order of colors. It list colors from? - correct answer ✔✔Long wavelengths to short wavelengths Which wavelength of ultra-violet radiation is absorbed by the ozone layer? - correct 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? - correct 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? - correct 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? - correct 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? - correct answer ✔✔bend toward the normal 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? - correct answer ✔✔bend away from the normal If light travels through a liquid at 140,000 miles per second, what is the index of liquid? - correct answer ✔✔1.32 If the optical center of lenses ( except for plano powers) are placed any place other than directly in front of the patients visual axis...? - correct answer ✔✔prismatic effect If a person moves his/her eyes away from the optical center of a lens to the left in the following RX, what would occur to the patients vision? -1.00 sph OU - correct answer ✔✔the patient would be viewing through a base in prism in the right lens and base out prism in the left lens, but the resulting prism would be equal, and although the image would be somewhat displaced, there would be no imbalance When light strikes a prism, the light ray is bent (deviated) toward the base and the image is displaced toward the - correct answer ✔✔apex How far will 2 prism diopters deviate light at 1m? - correct answer ✔✔2cm When light passes from a medium of lesser density, such as air to a medium of greater density, such as glass, the path of light is bent toward the? - correct answer ✔✔normal Which lens would produce with motion? - correct answer ✔✔minus Which lens would produce against motion? - correct answer ✔✔plus Compound lenses (sphero-cylinder lenses) combine a spherical surface with a? - correct answer ✔✔toric or cylindrical surface A principles meridians on a compound lenses are? - correct answer ✔✔90 degrees apart Plus cylinder lenses - correct answer ✔✔have the cylinder generated on the front surface Minus cylinder lenses - correct answer ✔✔have the cylinder generated on the back surface The optical center of a lens is that singular point which light passes though with out being - correct answer ✔✔deviated The wavelengths from longest to shortest are - correct answer ✔✔red, orange, yellow, green, blue, indigo, violet If the visible spectrum the red wavelength is the longest wavelength, travels fastest and bends - correct answer ✔✔less When were lenses first set in frames - correct answer ✔✔late in the 13th century Who were the first spectacle frame makers - correct answer ✔✔Goldsmiths Why did the FDA ban cellulose nitrate as a frame material? - correct answer ✔✔it was too flammable to be considered safe Why is plastic a popular material for spectacle frame? - correct answer ✔✔it can be easily molded and shaped What special care is required for nylon frames? - correct answer ✔✔periodic soaking in water overnight What plastic frame material is the only one that can be either pantographed or injection molded? - correct answer ✔✔Cellulose acetetate Which of the following plastics will shrink if overheated? - correct answer ✔✔polymide Because this material is black in its original form, this plastic must apply color through the use of baked- on enameling? - correct answer ✔✔Carbon The material that is recommended for cold snap insertion? - correct answer ✔✔polymide This material is the most difficult to adjust bc of its tendency to relax? - correct answer ✔✔Kevlar Half eyes are designed for? - correct answer ✔✔near only