What is the length of a simple pendulum with a period of 11.5 s?

The length of a simple pendulum with period 11.5 s = 32.86 m

Given data :

period ( T ) = 11.5 secs

acceleration due to gravity ( g ) = 9.8 m/s²

we will apply the formula below

Therefore L  =  

                      = ( 11.5 )² * 9.8 /  4 * (3.14)²

                      = 132.25 * 9.8 /  ( 39.4384 )

                      = 32.86 m

Hence the length of a simple pendulum with period 11.5 s = 32.86 m

Learen more about simple pendulum : link

the answer is b ) square root of 5