Two ions having masses in the ratio $1:1$ and charges in the ratio $1:2$ are projected into a uniform magnetic field perpendicular to the field with speeds in the ratio $2:3$. The ratio of the radii of the circular paths along which the two particles move is

The experimentally determined molar mass of a non-volatile solute,$BaCl_2$,in water by Cottrell's method,is

For all integers $n \geq 1$,which of the following is divisible by $9$?

The structure which prevents the entry of food into the respiratory tract is

$A$ charge $q$ is placed at the centre of the line joining two equal charges $Q$. The system of the three charges will be in equilibrium if $q$ is equal to:

$A$ hollow sphere of radius $R$ is filled completely with an ideal liquid of density $\rho$. The sphere is moving horizontally with an acceleration $2g$,where $g$ is the acceleration due to gravity. If the minimum pressure of the liquid is $P_0$,then find the pressure at the centre of the sphere.