Question

Time period of a simple pendulum will be double if we ___________

(a) Decrease the length 2 times

(b) Decrease the length 4 times

(c) Increase the length 2 times

(d) Increase the length 4 times

The question was posed to me in examination.

The doubt is from Wave Motion in division Waves of Engineering Physics I

Answer 1

Right option is (d) Increase the length 4 times

For explanation I would say: T=2π√(l/g)  or T∝√l

When the length is increased four times, time period gets doubled.