just a few quick communication questions...

1-is it possible to have total internal reflection for light incident from air onto water? why?

2-what is the angle of refraction when a light ray meets the boundary between two materials perpendicularly?

1. No. The refracted angle would be 90 deg, so

Nair*sinThetaincid=Nwater(sin90_
sinthetaincid=1.333

In Texas, sines don't go that high.

2. Perpendicular goes straight thru, no bending.

1. To answer the first question regarding total internal reflection for light incident from air onto water, we can use the concept of critical angle. Total internal reflection occurs when light travels from a medium with a higher refractive index to a medium with a lower refractive index, and the angle of incidence exceeds the critical angle.

The critical angle is the angle of incidence at which the refracted ray would have an angle of refraction of 90 degrees (perpendicular to the surface). It can be calculated using the formula:
critical angle = arcsin(n2/n1)

In this case, light is incident from air (typically with a refractive index of approximately 1) onto water (with a refractive index of approximately 1.33). Plugging these values into the formula, we can calculate the critical angle for air-water interface:
critical angle = arcsin(1.33/1) = arcsin(1.33) ≈ 49.5 degrees

So, if the angle of incidence is greater than 49.5 degrees, total internal reflection will occur at the air-water interface.

2. When a light ray meets the boundary between two materials perpendicularly, it means the angle of incidence is 0 degrees. According to the laws of refraction, the angle of refraction is determined by the relationship between the refractive indices of the two materials. The formula to calculate the angle of refraction is:
angle of refraction = arcsin(n1/n2)

When the incident angle is 0 degrees (i.e., perpendicular), the angle of refraction can be calculated as:
angle of refraction = arcsin(n1/n2) = arcsin(n1/ n2)

Since the angle of incidence is 0 degrees, the angle of refraction will also be 0 degrees. In this case, the light ray passes through the boundary without being bent or refracted.