Electric potential at any point is $V = - 5x + 3y + \sqrt {15} z$, then the magnitude of the electric field is

Two plates are $2\,cm$ apart, a potential difference of $10\;volt$ is applied between them, the electric field between the plates is.........$N/C$

An oil drop having charge $2e$ is kept stationary between two parallel horizontal plates $2.0\, cm$ apart when a potential difference of $12000\, volts$ is applied between them. If the density of oil is $900 \,kg/m^3$, the radius of the drop will be

The potential $V$ is varying with $x$ and $y$ as $V\, = \,\frac{1}{2}\,\left( {{y^2} - 4x} \right)\,volt.$ The field at ($1\,m, 1\,m$ ) is

The electric potential at a point $(x, y, z)$ is given by $V=-x^2y-xz^3 +4 $. The electric field at that point is  

Figure shows two equipotential lines in $x, y$ plane for an electric field. The scales are marked. The $x-$ component $E_x$ and $y$ -component $E_y$ of the electric field in the space between these equipotential lines are respectively :-