The the period of a conical pendulum in terms os its length (l), semi vertical angle (a) and acceleration due to gravity (g) is:

a) 1/2 pi (Sq rtof l x cosa/g )
b) 1/2 pi (sq rtof l x sin a /g)
c) 4 pi ( sq rt of l cos a/4g)
d) 4 pi ( Sq rt of l tan a/g)