The electric potential at any point as a function of distance $(x)$ in meter is given by  $V = 5x^2 + 10x -9 \,(volt)$ Value of electric field at $x = 1$ is......$Vm^{-1}$

A particle $A$ has charge $+q$ and particle $B$ has charge $+ 4q$ with each of them having the same mass $m$. When allowed to fall from rest through same electrical  potential difference, the ratio of their speed $V_A : V_B$ will be :-

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 large circular discs separated by a distance of $0.01 m$ are connected to a battery via a switch as shown in the figure. Charged oil drops of density $900 kg m ^{-3}$ are released through a tiny hole at the center of the top disc. Once some oil drops achieve terminal velocity, the switch is closed to apply a voltage of $200 V$ across the discs. As a result, an oil drop of radius $8 \times 10^{-7} m$ stops moving vertically and floats between the discs. The number of electrons present in this oil drop is (neglect the buoyancy force, take acceleration due to gravity $=10 ms ^{-2}$ and charge on an electron ($e$) $=1.6 \times 10^{-19} C$ )

If the electric potential at any point $(x, y, z) \,m$ in space is given by $V =3 x ^{2}$ volt. The electric field at the point $(1,0,3) \,m$ will be ............

A uniform electric field having a magnitude ${E_0}$ and direction along the positive $X - $ axis exists. If the potential $V$ is zero at $x = 0$, then its value at $X = + x$ will be