Situation 18.1 A tank holds a 1.44 m thick layer of oil that floats on a 0.96 m
ID: 1950410 • Letter: S
Question
Situation 18.1A tank holds a 1.44 m thick layer of oil that floats on a 0.96 m thick layer of brine. Both liquids are clear and do not intermix.
Point O is at the bottom of the tank, on a vertical axis. The indices of refraction of the oil and the brine are 1.40 and 1.52,
respectively.
11) In Situation 18.1, a ray originating at O reaches a point on the oil-air interface at the critical angle.
The distance of this point from the axis is closest to:
11)
A) 1.7 m B) 1.9 m C) 2.3 m D) 2.1 m E) 1.5 m
Explanation / Answer
Sin c = 1.40/1.52 = 0.92105 Critical angle, c = 67.1o Tan c = d/0.96 Hence, 2.365 = d/0.96 The distance d = 2.365x0.96 = 2.27 = 2.3 m; Choice (C)