Question

A particle address is dropped from the top of a tower of height h it takes time take to reach the ground

Answer 1

Not sure what exactly your question point out to but sure it will be about finding velocity of object/address this could be done by Conservation of Mechanical energy(I am ignoring friction due to air because of no clear indications).

So

KE=PE

1/2m$v^{2}$=mgh

$v^{2}$= 2gh

Hope so you get it ask if any doubt