Elements of natural philosophy (Volume 2-3) . Light passingfrom rarer todenser medium; Angle ofincidence taken90°; J- * A ft — = em m (8) from which results a maximum limit to the angle of Maximum limitrefraction. If m be taken equal to 1,52 for the atmos-to angle of x refraction; phere and crown glass, sin 0 = 0,657, or 0 = 41° 5 30, nearly; Example, atmosphere andcrown glass; for air and water, m = 1?33, and Atmosphere andwater; 0 = 48° 15; that is to say, the greatest angle of refraction which canexist when light passes from air into crown glass, is 41°5 30; and from air into water, 48° 15.
Elements of natural philosophy (Volume 2-3) . Light passingfrom rarer todenser medium; Angle ofincidence taken90°; J- * A ft — = em m (8) from which results a maximum limit to the angle of Maximum limitrefraction. If m be taken equal to 1,52 for the atmos-to angle of x refraction; phere and crown glass, sin 0 = 0,657, or 0 = 41° 5 30, nearly; Example, atmosphere andcrown glass; for air and water, m = 1?33, and Atmosphere andwater; 0 = 48° 15; that is to say, the greatest angle of refraction which canexist when light passes from air into crown glass, is 41°5 30; and from air into water, 48° 15. If the ray pass from a medium to another less dense, 180 NATURAL PHILOSOPHY Light passing m will be less than unity,from denser to an(j eqUal to the reciprocal rarer medium; _ of its former value ; Equa-tion (7) will then give sin sin <p ; Angle of taking the maximum value refraction taken . .. 1 90°; for sin <p = 1, we shall ob- tain from the same Equation, Fig. Consequence; sm <p = m 77 5 (») Examples; this value for the sine of the angle of incidence, whichcorresponds to the greatest angle of refraction when lightAnalogy; jjasses from any medium to one less dense, is the same as that found before for the greatest angle of refraction,when the incidence was taken a maximum, in the pas-sage of light from one medium to another of greater den-sity. In the case of air and glass, it is 0,657 ; correspond-ing to an angle of 41° 5 30; for air and water, theangle is 48° 15. If the angle <p be taken greater than that whose sine couciusion; is —, the angle of refraction, or emergence from the 771 denser medium, will be imaginary, and the light will bewholly reflected at the deviating surface. This maximumreflexion value for <p is called the angle of total reflexion. Light cannot, therefore, pass out of crown glass into air under agreater angle of incidence than 41 ° 5 30 , nor out ofwater into air under a greater angle than 48° 15. § 2
Size: 1569px × 1593px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, booksubjectmechanics, booksubjectopticsandphoto
