Explanation:
The time period of the pendulum T = 2π[tex]\sqrt{\frac{l}{g} }[/tex]
here l is the length of pendulum and g is the acceleration of gravity
Thus l = [tex]\frac{T^2 g}{4\pi^2 }[/tex]
and l = [tex]\frac{(12)^2 x 10}{4 x 9.8}[/tex] = 36 m approx
