There is no $S-S$ bond in

Beats are produced by two waves given by $y_1 = a \sin(2000 \pi t)$ and $y_2 = a \sin(2008 \pi t)$. The number of beats heard per second is

An air-cored coil has a self-inductance of $0.1 \ H$. $A$ soft iron core of relative permeability $1000$ is introduced,and the number of turns is reduced to $\left(\frac{1}{10}\right)^{\text{th}}$. The value of the new self-inductance is:

Which process is used for the removal of hardness of water?

The number of triangles that can be formed by choosing the vertices from a set of $12$ points,seven of which lie on the same straight line,is

The same retarding force is applied to stop a train. The train stops after $80 \ m$. If the speed is doubled,then the distance will be