Question

A person of height $\sqrt{2}$ m is standing on horizontal floor infront of a plane mirror inclined at an angle of ${45}^{\circ }$ with vertical. Minimum size of mirror required in meters, if person wants to see his full image is ? Eye of man is at 2 m from mirror (Write upto two digits after the decimal point.)

Answer 1

AB is object & CD is image.
pq is length of mirror required

From trapezium ABCD,
AB = CD = L , BP = PC = d
d = 2 m , L = $\sqrt{2}$ m
PQ = $d\tan \alpha =d\left(\frac{L\sin \theta }{2d+L\cos \theta }\right)=\frac{2}{5}=0.4$