Show how the three rays pass from the left, air side, through the curved surface
ID: 2018505 • Letter: S
Question
Show how the three rays pass from the left, air side, through the curved surface into the right, glass side. The glass has refractive index 2.0. The dot on the diagram below indicates the center of curvature for the lens surface. Extend the rays on the glass side until they intersect. Ray #1 is on the axis, and will be the reference. If the radius is 20 cm, determine where the parallel rays 2, 4 cm from the axis, and 3, 10 cm from the axis, intersect with ray 1, expressed as the distance from the front surface.
ray 2 = ? cm
ray 3 = ? cm
Explanation / Answer
Eperimental studies of the directions of the incident,reflected,and refracted rats at a smooth interface between two optical materials lead to the following conclusions: 1.The incident,reflected,and refrated rays and the normal to the surface all lie in the same plane.The plane of the three rays is perpendicular to the plane of the boundary surface between the two materials. 2.The angle of reflection ?r is equal to the angle of incidence ?a for all wavelengths and for any pair of materials.That is, ?r = ?a This relation,together with the observation that the incident and reflected rays and the normal all lie in the same plane,is called the law of reflection. 3.For monochromatic light and for a given pair of materials,a and b,on opposite sides of the interface,the ratio of the sines of the angles ?a and ?b,where both angles are measured from the normal to the surface,is equal to the inverse ratio of the two indexes of refraction: (sin?a/sin?b) = (nb/na) or na * sin?a = nb * sin?b (law of refraction) This experimental result,together with the observation that the incident and refracted rays and the normal all lie in the same plane,is called the law of refraction or Snell's law,after the Dutch scientist Willebrord Snell.