Question

(5.) Light propagates from air into a material whose index of refraction is two. At the instant shown, point a is just entering the new material. Point b is on the same wavefront as point a but is still in air. (a.) Using the dashed lines as a guide, determine the location of point a when point b reaches the bounda between the two materials. (b.) Use the new locations of points a and b to draw the wavefront once it is entirely in the new material. Hint: Remember that an index of 1.5 tells us that the speed of light inside that material is 2/3 that of the speed in the vacuum. (c.) Use that wavefront to draw the ray for the refracted beam of light. (d.) Indicate the angles of incidence and refraction on the figure. (e.) Repeat the same procedure but for light that is propagating from a material with index of refraction 1.5 into air. ni = 1 n = 1.5 n2 = 1 (f.) Do your results verify the statement made in the intro video that light bends toward the normal when it slows down and away from the normal when it speeds up? Explain why or why not.

Answer 1

(a.) Using the dashed lines as a guide, determine the location of point a when point b reaches the boundary between the two materials.


(b.) Use the new locations of points a and b to draw the wavefront once it is entirely in the new material. Hint: Remember that an index of 1.5 tells us that the speed of light inside that material is 2/3 that of the speed in the vacuum.


(c.) Use that wavefront to draw the ray for the refracted beam of light.

Sol: Here index of reraction of material is 1.5 or 2 ? some where it is mentioned 2 and somewhere 1.5 I have taken it 2 as it is given in figure.   

n] = n2 = 2

(e.) Repeat the same procedure but for light that is propagating from a material with index of refraction 1.5 into air

Sol: Here index of refraction is 1.5

n = 1.5