To get three images of a single object, One should have two plane mirror at an angle of

Options

A. `60^(@)`
B. `90^(@)`
C. `120^(@)`
D. `30^(@)`

Answer

B

Explanation

Consider the diagram where two plane mirrors are inclined at an angle `theta`.
Number of images formed is given by,
`n=(360^(@))/(theta)-1("For odd number of images")`
`Rightarrow 3=(360^(@))/(theta)-1Rightarrow (360^(@))/(theta)=4 Rightarrowtheta=90^(@)`