The length of shadow of a tower on the plane ground is $$\sqrt 3 $$ times the height of the tower. The angle of elevation of sun is
a) 45°
b) 30°
c) 60°
d) 90°

Answer: b
Explanation: Let AB be tower and BC be its shadow
Let AB = x

$$\eqalign{ & {\text{Then}}\,BC = \sqrt 3 \times x = \sqrt 3 \,x \cr & \tan \theta = \frac{{AB}}{{BC}} \cr & \,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\, = \frac{x}{{\sqrt 3 \,x}} \cr & \,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\, = \frac{1}{{\sqrt 3 }} \cr & \,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\, = \tan {30^ \circ } \cr & \theta = {30^ \circ } \cr} $$
Angle of elevation of the sun$${\text{ = }}{30^ \circ }$$