# The ratio of the length of a rod and its shadow is $1: \sqrt{3}$ The angle of elevation of the sum is.

A. 30° B. 45° C. 60° D. 90° Answer: Option A
Let AB be rod and BC be its shadow So that, $A B: B C=1: \sqrt{3}$ Let $\theta$ be the angle of elevation $\begin{array}{l} \therefore \tan \theta=\frac{A B}{B C}=\frac{1}{\sqrt{3}}=\tan 30^{\circ} \\ \left(\because \tan 30^{\circ}=\frac{1}{\sqrt{3}}\right) \\ \therefore \theta=30^{\circ} \end{array}$ ∴ Hence angle of elevation $=30^{\circ}$