http://web.mst.edu/~rogersda/military_service/periscopes.jpg Submarines carry all kinds of extendable devices in their sail which allow them to sense above the ocean's surface. This shows a deployed periscope (on left) and other electronic surveillance and communications probes.
c. If the ray is incident on surface BC , from which surface and at what angle will the ray leave the block?
Angle of incidence = 60 o
Angle of refraction = 32.3 o
Critical angle = 38.1 o
Draw refracted ray2. Measure angle of ray2 hitting block. Angle is greater than critical angle of 38.1 o thus ray3 will reflect. Draw ray3 following Law of Reflection. Measure angle of ray3. Since it is the same angle as ray2, it will refract out at the same angle. Thus ray4 refracts at 60 o from surface AD . 30 A B C D 32.3 57.7 32.3 60