At a certain distance from a point charge the electric field is $500\,V/m$ and the potential is $3000\,V$. What is this distance......$m$

Electric potential is given by

$V = 6x - 8x{y^2} - 8y + 6yz - 4{z^2}$

Then electric force acting on $2\,C$ point charge placed on origin will be......$N$

The variation of potential with distance $x$ from a fixed point is as shown in figure. The electric field at $x =13\,m$ is......$volt/meter$

Two metal pieces having a potential difference of $800 \;V$ are $0.02\; m$ apart horizontally. A particle of mass $1.96 \times 10^{-15} \;kg$ is suspended in equilibrium between the plates. If $e$ is the elementary charge, then charge on the particle is

Which of the following is true for the figure showing electric lines of force? ($E$ is electrical field, $V$ is potential)

For a charged spherical ball, electrostatic potential inside the ball varies with $r$ as $V =2 ar ^2+ b$. Here, $a$ and $b$ are constant and $r$ is the distance from the center. The volume charge density inside the ball is $-\lambda a \varepsilon$. The value of $\lambda$ is $...........$. $\varepsilon=$ permittivity of medium.