I m stuck with this home work question, any kind of or hint to solve this question would be appreciated?

light from ray A refracts from material 1 (n1 = 1.60) into a thin layer of material 2 (n2 = 1.77), crosses that layer, and is then incident at the critical angle on the interface between materials 2 and 3 (n3 = 1.42). (a) What is the value of incident angle θA (in o)? (b) If θA is decreased, does part of the light refract into material 3





Light from ray B refracts from material 1 into the thin layer, crosses that layer, and is then incident at the critical angle on the interface between materials 2 and 3. (c) What is the value of incident angle θB? (d) If θB is decreased, does part of the light refract into material 3 (1 depicts "yes", 0 - otherwise)?

I m stuck with this home work question, any kind of or hint to solve this question would be appreciated?
http://www.sasked.gov.sk.ca/docs/physics...





Draw a picture and treat each piece of material as a separate problem with the calculated result from one used as the input angle of the next :





material1 -%26gt; material 2 -%26gt; material -%26gt;

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