Suppose a luminous sphere of radius R1 (such as the Sun) is surrounded by a uniform atmosphere of radius R2>R1 and index of refraction n. When the sphere is viewed from a location far away in vacuum, what is its apparent radius when R2>nR1
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Solution
Assume the viewer is far away to the right. In ANS. FIG. P35.86(a), a ray directed toward the viewer comes tangentially from the edge of the glowing sphere and emerges from the atmosphere at angle θ2. The apparent radius of the glowing sphere is R3 as shown. For the figure, we see that sinθ1=R1R2 and sinθ2=R3R2 Then,nsinθ1=1.00sinθ2 and nR1R2=R3R2→R3=nR1