The angle between the particle velocity and wave velocity in a transverse wave is [except when the particle passes through the mean position]
A metallic sphere of radius $R$ carrying a charge $q$ is kept at certain distance from another metallic sphere of radius $\mathrm{R} / 4$ carrying a charge Q . What is the electric flux at any point inside the metallic sphere of radius R due to the sphere of radius $\mathrm{R} / 4$ ?

You are given a dipole of charge $+q$ and $-q$ separated by a distance $2 R$. A sphere ' $A$ ' of radius ' $R$ ' passes through the centre of the dipole as shown below and another sphere ' $B$ ' of radius ' $2 R$ ' passes through the charge +q . Then the electric flux through the sphere A is

A potential at a point A is -3 V and that at another point B is 5 V . What is the work done in carrying a charge of 5 m C from B to A ?