Total Internal reflection

Question 1

What is the equation for monochromatic light propagating through two different glasses with two different indices of refraction?

Answer 1

~ na = sinΦv/sinΦa
~ nb = sinΦv/sinΦb
~ nasinΦa = nbsinΦb

Question 2

What is the equation for total internal reflection?

Answer 2

~ sinΦcrit = nair/nglass *sin(90) = 0.67

~ ncrit = 42 degrees

Question 3

When can total internal reflection occur?

Answer 3

~ only if n outside the medium is smaller than n inside the medium

Question 4

Why are glass prisms used as mirrors for monochromatic light?

Answer 4

~ less susceptible to polished surface corrosion than polished metal