Physics multiple choice question plz help?

Question

A pendulum with a string of length 2 m has a period of about 2.8 s. What would be the period of the pendulum if the length of the string were increased to 8 m?
A. 1.4 s
B. 5.6 s
C. 11.2 s
D. 44.8 s

Answer 1

 

Initial length ,l1=2 m

Initial time,T1=2.8 s

Increased length,l2=8 m

Relation

T1/T2=sqrt(l1/l2)

2.8/T2=sqrt(2/8)

2.8/T2=1/2

T2=5.6 s

Option B is correct