When a plane mirror is placed horizontally on level ground at a distance of 60 m from the foot of a tower, the top of the tower and its image in the mirror subtend and angle of `90^@` at the eye. The height of the tower is

Options

A. 30 m
B. 60 m
C. 90 m
D. 120 m

Answer

B

Explanation

(b) Given, AC=60 m and `angleBCB'=90^(@)`

From the figure,
`therefore` Angle, `angleBCA=(angleBCB')/2=45^(@)`
We have, `tan45^(@)=h/(AC)`
`rArr` AC=h and AB=AC=60 m