00:01
Alright, here we've got a problem where we have the sun, and we've got a scuba diver underneath the water.
00:10
Scooby diver, let's drive right here.
00:13
Scoop diver.
00:15
Okay, and he sees the sun at a 45 degree angle from the horizontal, and we are asked, okay, what is the angle that the sun is actually at from the horizontal? what is this theta? and so we're going to use snell's law, which is n1, sine theta 1 equals n2, n2, sine of theta 2.
00:43
Where ends are the indices of a fraction.
00:45
I know that the end of air is generally given as 1.
00:49
The end of the water is generally accepted 1 .33.
00:55
And be careful with your thetas, though, because we always have to make these thetas relative to the normal line.
01:03
And so this angle, because it's one of those triangles, is 45 degrees.
01:10
And so the theta in our equation is actually going to be this theta.
01:15
So we should have to remember to minus 90 at the end when we do our calculations...