1. The problem statement, all variables and given/known data A ray of light is incident on a flat surface of a block of gallium phosphide that is surrounded by water. The angle of refraction is 8.0°. Find the angle of reflection. 2. Relevant equations n1 sin(theta1) = n2 sin(theta2) 3. The attempt at a solution I keep finding different values for the index of refraction of gallium phosphide... 3.20 (which was wrong), 3.8 (also wrong)... can anyone verify what the correct number is? Using 3.20 as the index of refraction of gallium phosphide and 1.33 as the index of refraction of water: sin(theta) = (3.20 * sin(8.0 degrees)) / 1.33 theta = 19.56 degrees (incorrect) Each time I'm submitting this question, it says my answer is within 10% of the correct answer, leading me to think that it's an error with the refractive index value. Thank you!!!