Two point charges '$$q 1$$' and '$$q 2$$' are separated by a distance '$$d$$'. What is the increase in potential energy of the system when '$$q 2$$' is moved towards '$$q 1$$' by a distance '$$\mathrm{x}$$' ? $$(x < d)(\frac{1}{4 \pi \varepsilon_0}=K$$, constant)

Three point charges $$\mathrm{+Q,+2q}$$ and $$+\mathrm{q}$$ are placed at the vertices of a right angled isosceles triangle. The net electrostatic potential energy of the configuration is zero, if $$Q$$ is equal to

Two electric dipoles of moment $$\mathrm{P}$$ and $$27 \mathrm{P}$$ are placed on a line with their centres $$24 \mathrm{~cm}$$ apart. Their dipole moments are in opposite direction. At which point the electric field will be zero between the dipoles from the centre of dipole of moment P?

An electron of mass '$$\mathrm{m}$$' and charge '$$\mathrm{q}$$' is accelerated from rest in a uniform electric field of strength '$$E$$'. The velocity acquired by the electron, when it travels a distance '$$\mathrm{L}$$', is