The length of a pendulum changes from `1m` to `1.21m`. The percentage change in its period is

Options

A. 0.2
B. 0.21
C. 0.1
D. 0.11

Answer

C

Explanation

`T alpha sqrt(l)`
`(T_(1))/(T_(2)) = sqrt((l_(1))/(l_(2)))rArr (T_(1))/(T_(2)) = sqrt((1)/(1.21))`
`rArr T_(2) = 1.1 T_(1)` = Time period increases by 10%