Question

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 increases length is?

(a) 50%

(b) 21%

(c) 30%

(d) 10.5%

Answer 1

Correct choice is (d) 10.5%

The explanation: Time period,

T=2π√(l/g)

The percentage increase in a time period is given by,

∆T/T×100=1/2×∆l/l×100

∆T/T×100=1/2×21%=10.5%.