A mass $x$ gram is suspended from a light spring. It is pulled in downward direction and released so that mass performs S.H.M. of period T. If mass is increased by Y gram, the period becomes $\frac{4 \mathrm{~T}}{3}$. The ratio of $\mathrm{Y} / \mathrm{x}$ is

Three inductances are connected as shown in the figure. The equivalent inductance between A and b is

A disc of mass ' $m$ ' and radius ' $r$ ' rolls down an inclined plane of height ' $h$ '. When it reaches the bottom of the plane, its rotational kinetic energy is ( $\mathrm{g}=$ acceleration due to gravity)

The frequency of a stretched uniform wire of length $L$ under tension is in resonance with the fundamental frequency of a closed pipe of same length. If the tension in the wire is increased by 8 N , it is in resonance with the first overtone of the same closed pipe. The initial tension in the wire is