(a) When two mirrors are kept perpendicular to each other i.e., θ = 90°,

then n = 360º\over 90º = 4

n = 4, is even so the number of images is n – 1

Therefore,

n – 1 = 4 – 1 = 3

(b) When two mirrors are kept at 60° to each other,

then n = 360º\over 60º = 6

n = 6, is even so the number of images is n – 1,

Therefore,

n – 1 = 6 – 1 = 5

Hence, **for two mirrors kept at 60° to each other, five images are formed for an object kept in between them.**