The length of a simple pendulum executing simple harmonic motion is increased by `21%`. The percentage increase in the time period of the pendulum of increased lingth is.

Explanation

Time period of a simple pendulum is
`T=2pisqrt((l)/(g))` or `Tpropl^(1//2)` or `T=kl^(1//2)`
`(DeltaT)/(T)=(1)/(2)(Deltal)/(l)` Given `(Deltal)/(l)xx100=21%`
`%` increase in time period
`=(DeltaT)/(T)xx100=(1)/(2)/(Deltal)/(l)xx100=(1)/(2)xx21%=10.5%`