Electric Field (Discrete and Continuous Charge Distributions)

Assertion: Due to two point charges electric field and electric potential cannot be zero at some point simultaneously.

Reason: Field is a vector quantity and potential is a scalar quantity.

Two point charges $q$ and $2q$ are placed some distance apart. If the electric field at the location of $q$ be $E$, then that at the location of $2q$ will be

The maximum field intensity on the axis of a uniformly charged ring of charge $q$ and radius $R$ will be

The fig. shows lines of constant potential in a region in which an electric field is present. The value of the potential are written in brackets of the points $A, B$ and $C,$ the magnitude of the electric field is greatest at the point -

An equipotential surface and an electric line of force:

A long cylindrical shell carries a positive surface charge $\sigma$ in the upper half and a negative surface charge $-\sigma$ in the lower half. The electric field lines around the cylinder will look like the figure given in: (figures are schematic and not drawn to scale)

The figure shows the electric lines of force emerging from a charged body. If the electric fields at $A$ and $B$ are $E_A$ and $E_B$ respectively and if the distance between $A$and $B$ is $r,$ then

Two large circular discs separated by a distance of $0.01 \mathrm{m}$ are connected to a battery via a switch as shown in the figure. Charged oil drops of density $900 \mathrm{kg}{ \mathrm{m}}^{-3}$ 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 $200 \mathrm{V}$ across the discs. As a result, an oil drop of radius $8\times {10}^{-7} \mathrm{m}$ 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 $=10{ \mathrm{ms}}^{-2}$ and charge on an electron $\left(\mathrm{e}\right)=1.6\times {10}^{-19}\mathrm{C}$)

Infinite number of charges of magnitude $6 \mu \mathrm{C}$ each are lying at $y=2, 4, 8, 16\dots$ metre on $Y$-axis. The value of electric field intensity at point $y=0$ due to these charges will be $a\times {10}^4 \mathrm{N} {\mathrm{C}}^{-1}$, find the value of $a$,

The tracks of three charged particles in a uniform electrostatic field are shown in the figure. Which particle has the highest charge to mass ratio?

If the flux of the electric field through a closed surface is zero then

The constant $\mathrm{k}$ in Coulomb’s law depends on

A metal plates of capacitor of area $0.01 {\mathrm{m}}^2$ carries a charge of $100 \mathrm{\mu C}$. Calculate the outward pull on plate (in newton).

A metallic shpere is placed in a uniform electric field. The line of force follow the path(s) shown in the figure as,

The maximum field intensity on the axis of a uniformly charged ring of charge $q$ and radius $R$ will be

A thin conducting ring of radius $R$ is given a charge $+Q$. The electric field at the centre $O$ of the ring due to the charge on the part $AKB$ of the ring is $E$. The electric field at the centre due to the charge on the part $ACDB$ of the ring is

The tracks of three charged particles in a uniform electrostatic field are shown in the figure. Which particle has the highest charge to mass ratio?

If the flux of the electric field through a closed surface is zero

The constant $\mathrm{k}$ in Coulomb’s law depends on