As observed from the top a light house, 120√3 m above the sea level, the angle of depression of a ship sailing towards it changes from 30° to 60°. The distance travelled by the during the period of observation is:

Answer: Option A

Solution

Answer: Option A

Solution:

$$\begin{array}{rl}& \sqrt{3}\to 120\sqrt{3}\\ & 1\text{u}\to 120\\ & 2\text{u}\to 120\times 2=240\text{m}\end{array}$$