Question

What is the critical angle theta c for total internal reflection if the material is clear acrylic, with a refractive index of 1.5?

62 degrees, 90 degrees , 42 degrees , or 49 degrees

:/

Answer 1

here we have to apply the law of Snell, so we can write this:
\[n\sin {\theta _c} = 1\]

Answer 2

then:
\[\large \sin {\theta _c} = \frac{1}{n} = \frac{1}{{1.5}}\]

Answer 3

so we get 0.666666667?

Answer 4

ok! Now we have to compute this:
\[{\theta _c} = \arcsin \left( {0.667} \right) = ...\]

Answer 5

\[\large {\theta _c} = \arcsin \left( {0.667} \right) = ...\]

Answer 6

41.835? so our solution is 42 degrees?

Answer 7

yes!

Answer 8

yay! thank you:)

Answer 9

:)