The time period of oscillation of a mass suspended by a spring (force constant k) is T. If the spring is cut into three equal pieces, the force constant of each part and the periodic time, if the same mass is suspended from one piece are
3k,T3
k1l1=kl= constant ⇒k1(13)=kl⇒k1=3k
⇒T=2π√mk1=2π√m3k=T√3
Hence the correct option is 3k,T√3