How to calculate angle of incidence when given the angle of refraction?

17.December, 2009

I am having a problem calculating this question:

Light travels from water to glass at some angle and refracts at 48°. Find the angle of incidence.

I know how to find the angle of refraction when given the angle of incidence but not the other way around.

You use the same eqn Snell’s Law. You just solve for thetaA not thetaB

nA*sin(thetaA) = nB*sin(thetaB) Here nA = 1.333 thetaA = ? nB = 1.50 thetaB = 48

So sin(thetaA) = nB/nA*sin(thetaB) or thetaA = arcsin(nB/nA*sin(thetaB)) =

thetaA = arcsin(1.50/1.333*sin(48)) = 56.7

Geschrieben von: admin Zufinden in: angling

1 Meinung für “How to calculate angle of incidence when given the angle of refraction?”

  1. Debbie sagt:
    17.December, 2009 um 9:58 am

    You use the same eqn Snell’s Law. You just solve for thetaA not thetaB

    nA*sin(thetaA) = nB*sin(thetaB) Here nA = 1.333 thetaA = ? nB = 1.50 thetaB = 48

    So sin(thetaA) = nB/nA*sin(thetaB) or thetaA = arcsin(nB/nA*sin(thetaB)) =

    thetaA = arcsin(1.50/1.333*sin(48)) = 56.7
    References :

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