ABO Practice Test Questions And Correct Answers, Over 400 Multiple choice Questions And Answers.

ABO Practice Test Questions And Correct Answers, Over 400 Multiple choice Questions And Answers. When discussing thick lenses, the factors which are considered in computing the lens power are: a. front curve, thickness and index b. back curve, thickness and index c. front curve, back curve and thickness d. front curve, back curve, thickness and index d. front curve, back curve, thickness and index Toric transposition shows: a. lens thickness b. power in principal meridians c. the power of the ADD d. the lens diameter b. power in principal meridians Increasing the diameter of a minus power lens always increases its: a. vertex power b. center thickness c. weight d. refractive index c. weight The optical center of a round segment is located: a. at the very top of the segment b. in the geometric center of the segment c. 5 mm from the top of the segment d. at the very bottom of the segment b. in the geometric center of the segment The base curve of any multifocal lens is found on the surface containing the: a. cross curve b. cylinder surface c. segment d. ocular curve c. segment Normal slab-off (bicentric grind) is ground on the lens whose vertical meridian has the: a. strongest curves b. most plus power c. least plus power d. least minus power c. least plus power The refractive error indicated by the Rx +1.75 -2.75 x 090 is: a. compound hyperopic astigmatism b. compound myopic astigmatism c. simple myopic astigmatism d. mixed astigmatism d. mixed astigmatism Tempering a lens by heat treating results in a lens being: a. less resistant to impact b. more resistant to impact c. more resistant to surface scratching d. impossible to break b. more resistant to impact A slab-off lens is for the correction of: a. astigmatic errors b. excessive weight of lens c. excessive prism imbalance at the reading level d. exotropia c. excessive prism imbalance at the reading level Chem-tempering makes a glass lens more impact resistant by placing the lens in a potassium nitrate bath. The lens undergoes a process known as: a. ion exchange b. iron oxide activation c. silver halide transfer d. thermal bleaching a. ion exchange Which wavelengths of light have been indicated as possible contributors to the onset of cataracts? a. 400-520 nm b. 520-635 nm c. 350-400 nm d. 635-750 nm c. 350-400 nm When the lenses are laid out and marked for cutting and edging, the lenses are usually decentered so as to correspond to the patient's pupillary distance after lenses are inserted. This is done for the following reason: a. to avoid unwanted prism b. for cosmetic effect c. to use off-center lenses d. to avoid thick edges on the nasal side a. to avoid unwanted prism 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 A 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 produces 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 White light is broken into its component colors when it is: a. diffracted b. refracted c. reflected d. diffracted or refracted d. diffracted or refracted To the viewer; the image seen in a plane mirror appears to be: a. inverted b. one-half as large as the object c. twice as large as the object d. as far behind the mirror as the object is in front of it d. as far behind the mirror as the object is in front of it The velocity of light is the least in: a. air b. polycarbonate c. water d. flint glass d. flint glass A lens dispersing white light into its component colors is an example of: a. achromatic abberration b. isochromatic abberation c. chromatic abberation d. newton's fringes c. chromatic abberation The optical center of a lens is: a. at the geometric center b. on the 180 line c. at the point where "A" and "B" measurements meet d. a lens location of zero deviation of the optical axis d. a lens location of zero deviation of the optical axis Light rays passing through a prism are deviated: a. toward the apex b. through an angle equal to the apex angle c. toward the base d. through the base c. toward the base Light travels outward in all directions from its source. The best explanation of this is that light takes the form of: a. radiated energy b. luminous waves c. wave fronts d. straight lines c. wave fronts The distance between the crest of one wave and the crest of the next one is called: a. wave front b. wave band c. wavelength d. amplitude c. wavelength The interpretation of the range of wavelengths of visible light varies but is generally accepted as lying between: a. 100 and 1000 nm b. 300 and 400 nm c. 400 and 700 nm d. 500 and 800 nm c. 400 and 700 nm The breaking up of white light into its component colors by a lens or prism is called: a. diffraction b. diffusion c. dispersion d. refraction c. dispersion The color in white light that is refracted the most after passing through a refracting test medium is: a. red b. yellow c. blue d. violet d. violet The reflection of light from a surface is most influenced by: a. the index of refraction of the surface medium b. the surface coating c. the regularity of the surface d. AR coating c. the regularity of the surface Light rays originating at a distant point source are described as being: a. divergent b. convergent c. parallel d. refracted c. parallel The incident ray, the reflected ray and the normal all lie: a. in two planes, one perpendicular to the other b. in the same plane c. in two planes, each opposite the other d. together, based on the angle of incidence b. in the same plane The bending of a ray of light when it goes from one medium to another is called: a. diffraction b. reflection c. refraction d. diffusion c. refraction A ray of light, passing from a dense to a less dense medium is bent: a. away from the normal b. toward the normal c. perpendicular to the normal d. an amount equal to the angle of incidence a. away from the normal The concept or use of the term "normal" is that it is an imaginary line that is: a. lying parallel to the refracting or reflecting surface b. perpendicular to the incident ray at the point of contact with the medium c. perpendicular to the medium's surface at the point of incidence of the ray d. perpendicular to the refracted or reflected ray at the point of contact with the medium c. perpendicular to the medium's surface at the point of incidence of the ray A correct statement regarding the law of refraction is that: a. light bends away from the normal when it enters a medium denser than the one in which it was traveling b. light bends toward the normal when it enters a medium denser than the one in which it was traveling c. the angle of refraction is equal to the angle of incidence d. the angle of refraction and the angle of incidence lie in different planes b. light bends toward the normal when it enters a medium denser than the one in which it was traveling Any bundle of rays passing through a converging lens is made: a. nearer to the parallel b. nearer to the critical angle c. more converging d. less converging than before c. more converging The ray that can pass through a lens without being refracted is called: a. the critical ray b. a normal ray c. the chief ray d. the axial ray d. the axial ray The angle of incidence, for which the angle of refraction is 90 degrees is called the: a. critical ray b. emergent ray c. angle of reflection d. critical angle d. critical angle When parallel incoming rays strike a convex mirror, the reflected rays: a. are made convergent b. seem to focus in front of the mirror c. seem to originate from behind the mirror d. are reflected parallel to the optical axis c. seem to originate from behind the mirror A ray entering a less dense medium, striking the interface at an angle greater than the critical angle will be: a. refracted at an angle less than the critical angle b. refracted at an angle equal to the incident angle c. reflected partly and refracted partially d. totally reflected internally d. totally reflected internally The image formed at the secondary focal point of a converging lens is: a. a virtual image b. larger in size than the object c. equal in size to the object d. a real image d. a real image The image formed in the eye is: a. real, inverted and smaller b. inverted, virtual and reverted c. erect, reverted and real d. real, virtual and erect a. real, inverted and smaller Real object rays from a point source: a. are only diverging b. sometimes are converging c. always diverge but are almost parallel at infinity d. always form a real image a. are only diverging In a convergent lens, an object point located at infinity will be focused at: a. the primary focal point b. the secondary focal point c. the center curvature of the first surface d. a point midway between the lens and the center of curvature b. the secondary focal point Of the following aberrations, which is the greatest concern to a spectacle wearer? a. spherical aberration b. coma c. chromatic aberration d. oblique aberration d. oblique aberration One of the following lens aberrations is basically the same in effect as the light dispersing property of prisms. It is: a. spherical aberration b. chromatic aberration c. distortion d. astigmatism b. chromatic aberration The focal length of a thick lens is determined by the: a. curvature of its refracting surfaces, the thickness of the lens and its index of refraction b. curvature of its reflecting surfaces and the width of the lens c. brightness of the object light, the angle of incidence and the object distance d. angle of incidence, the angle of reflection and the center thickness of the lens a. curvature of its refracting surfaces, the thickness of the lens and its index of refraction When a ray of white light strikes a prism it: a. disperses the light into a spectrum and deviates the rays toward the base of the prism and the image toward the apex b. disperses the light into a spectrum and deviates the rays toward the base of the prism and the image to the base c. disperses the light into a spectrum and deviates the image toward the base of the prism and the rays to the apex d. deviates the long wavelengths more than the short wavelengths a. disperses the light into a spectrum and deviates the rays toward the base of the prism and the image toward the apex A lens has a chromatic aberration when the following condition is present: a. wrong sphere power b. there is cylinder power induced c. there is color dispersion d. the axis is wrong c. there is a color dispersion The lens aberration that produces a shorter focal length for rays near the edge of the lens than for rays near the the optical axis is called: a. coma b. curvature of field c. chromatic aberration d. spherical aberration d. spherical aberration A corrected curve lens is a lens: a. that has the front curve compensated for the thickness b. that has reduced chromatic aberration c. that has a base curve chosen to reduce peripheral power errors d. with aspheric surfaces c. that has a base curve chosen to reduce peripheral power errors