Question

why are hilly area are most prone to lightining

Answer 1

Electricity always seeks the shortest path to its final destination. On a mountain or tall hill, that is the shorter path than to a level plain. However, even on a level area you do not want to be the tallest object around and you definitely do not want to seek cover under a tall tree for the same reason.

Answer 2

because lightning usually falls on sharp peak like structures such as tower , mountains , etc .