Passage 3 (Questions 74-76)
When two plane mirrors subtend an angle θ between them, then a ray of light incident parallel to one of them retraces its path after n reflections such that nθ=c (where c is a constant)
The graph between n and θ will
(a) be continuous but not differentiable
(b) be continuous and differentiable
(c) Not be continuous
(d) Can't say