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: a
Explanation: Let AB be rod and BC be its shadow
So that AB : BC = 1 : $$\sqrt 3 $$
Let $$\theta $$ be the angle of elevation

$$\eqalign{ & \tan \theta = \frac{{AB}}{{BC}} = \frac{1}{{\sqrt 3 }} = \tan {30^ \circ } \cr & \,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\left( {\because \tan {{30}^ \circ } = \frac{1}{{\sqrt 3 }}} \right) \cr & \theta = {30^ \circ } \cr} $$
Hence angle of elevation $$ = {30^ \circ }$$