$A$ child swinging on a swing in a sitting position stands up. What will happen to the time period of the swing?

$A$ small sphere oscillates simple harmonically in a watch glass whose radius of curvature is $1.6 \text{ m}$. The period of oscillation of the sphere is (Acceleration due to gravity $g = 10 \text{ m/s}^2$)

Two simple pendulums of length $0.5\, m$ and $2.0\, m$ respectively are given small linear displacement in one direction at the same time. They will again be in the phase when the pendulum of shorter length has completed .... oscillations.

$A$ bob of mass $m$ suspended by a thread of length $l$ undergoes simple harmonic oscillations with time period $T$. If the bob is immersed in a liquid that has density $1/4$ times that of the bob and the length of the thread is increased by $1/3$ of the original length,then the time period of the simple harmonic oscillations will be :-

Two simple pendulums are given: the first has a bob of mass $M_1$ and length $L_1$,and the second has a bob of mass $M_2$ and length $L_2$. Given $M_1 = M_2$ and $L_1 = 2L_2$. If the vibrational energy of both is the same,which of the following statements is correct?

The time period of a simple pendulum is $T$. If its length is increased by $21\%$,what is the percentage increase in its time period?