1. The problem statement, all variables and given/known data Calculate the angle of incidence for an angle of refraction of 10° for a) Diamond (2.42) to air θ2=Angle of refraction=10° n2=Index of refraction on refractive medium=1 n1=index of refraction on incident medium=2.42 θ1=? 2. Relevant equations n1sinθ1=n2sinθ2 3. The attempt at a solution The book's answer tells me the answer is 24.8° I rearranged the equation to find theta1 or the angle of incidence θ1=sin inverse(n2sinθ2/n1) I substituted the values and I got 4.1° Can someone help me? I can't figure out what I did wrong. Light is coming from a dense medium to a less dense medium (diamond to air) so where the incident ray originated from the dense medium which is n2. So confused..