List of top Physics Questions on Electrostatics asked in JEE Main

A point charge $q = 1\,\mu\text{C}$ is located at a distance $2\,\text{cm}$ from one end of a thin insulating wire of length $10\,\text{cm}$ having a charge $Q = 24\,\mu\text{C}$, distributed uniformly along its length, as shown in the figure. Force between $q$ and wire is ________ N.

The dimension of $\dfrac{1}{2}\varepsilon_0 E^2$ is

There are three co-centric conducting spherical shells $A$, $B$ and $C$ of radii $a$, $b$ and $c$ respectively $(c>b>a)$ and they are charged with charges $q_1$, $q_2$ and $q_3$ respectively. The potentials of the spheres $A$, $B$ and $C$ respectively are:

Match List-I with List-II.

Choose the correct answer from the options given below :}

Consider two identical metallic spheres of radius $R$ each having charge $Q$ and mass $m$. Their centers have an initial separation of $4R$. Both the spheres are given an initial speed of $u$ towards each other. The minimum value of $u$, so that they can just touch each other is :
(Take $k = \frac{1}{4 \pi \epsilon_0}$ and assume $kQ^2>Gm^2$ where $G$ is the Gravitational constant)

The electrostatic potential in a charged spherical region of radius $r$ varies as $V = ar^{3} + b$, where $a$ and $b$ are constants. The total charge in the sphere of unit radius is $a \times \pi \varepsilon_{0}$. The value of $a$ is ___.
(Permittivity of vacuum is $\varepsilon_{0}$)

Three parallel plate capacitors each with area $A$ and separation $d$ are filled with two dielectric ($k_1$ and $k_2$) in the following fashion. ($k_1>k_2$) Which of the following is true?

Find electric field intensity $ \vec{E} $ at the centre of the circle shown in the figure.

Diagram shows three arrangements of dielectric in a capacitor. Arrange the capacitors in increasing order of capacitance between A and B if $K_1>K_2$.

Two spheres having equal mass $ m $, charge $ q $, and radius $ R $, are moving towards each other. Both have speed $ u $ at an instant when the distance between their centers is $ 4R $. Find the minimum value of $ u $ so that they touch each other.

There are two point charges, one at the vertex and the other at the face of a cube as shown. Find the electric flux through the cube.

A $12\,\text{F}$ capacitor is connected to a $5\,\text{V}$ battery and fully charged. After disconnecting the battery, it is connected in parallel to an uncharged $6\,\text{F}$ capacitor. Find the final charge on the $6\,\text{F}$ capacitor.

In the following configuration of charges. Find the net dipole moment of the system :

If the electric potential is $V = 500$ volts at the point $(10,\,20)$ and the electric field is given by \[ \vec{E} = 10x\,\hat{i} + 5y\,\hat{j}\ \text{N/C}, \] find the potential at the origin.

A parallel plate capacitor with plate separation 5 mm is charged by a battery. On introducing a mica sheet of 2 mm while battery is connected, it is found that it draws 25% more charge. The dielectric constant of mica is :

A simple pendulum with a bob (mass $ m $ and charge $ q $) is in equilibrium in the presence of a horizontal electric field $ E $. Then, the tension in the thread is $ F_1 $. Given $ \frac{F_1}{F_2} = \frac{2}{\sqrt{\alpha}} $, find $ \alpha $.

Three small identical bubbles of water having same charge on each coalesce to form a bigger bubble. Then the ratio of the potentials on one initial bubble and that on the resultant bigger bubble is:

When there is no dielectric, the value of capacitance of a capacitor is $C$. Now some dielectrics are inserted in this capacitor as shown in the diagram. If the new capacitance becomes $\dfrac{nC}{3}$, then find the value of $n$ to the nearest integer

Identify the correct statements:
[A.] Effective capacitance of a series combination of capacitors is always smaller than the smallest capacitance of the combination.
[B.] When a dielectric medium is placed between charged plates of a capacitor, displacement of charges cannot occur due to insulation property of dielectric.
[C.] Increasing area of a capacitor plate or decreasing thickness of dielectric is an alternate method to increase the capacitance.
[D.] For a point charge, concentric spherical shells centered at the location of the charge are equipotential surfaces.
Choose the correct answer from the options given below:

Two point charges of $1\,\text{nC}$ and $2\,\text{nC}$ are placed at two corners of an equilateral triangle of side $3$ cm. The work done in bringing a charge of $3\,\text{nC}$ from infinity to the third corner of the triangle is ________ $\mu\text{J}$. \[ \left(\frac{1}{4\pi\varepsilon_0}=9\times10^9\,\text{N m}^2\text{C}^{-2}\right) \]

The velocity ($v$) – distance ($x$) graph is shown in the figure. Which graph represents acceleration ($a$) versus distance ($x$) variation of this system?

Two resistors $2\,\Omega$ and $3\,\Omega$ are connected in the gaps of a bridge as shown in the figure. The null point is obtained with the contact of jockey at some point on wire $XY$. When an unknown resistor is connected in parallel with $3\,\Omega$ resistor, the null point is shifted by $22.5\,\text{cm}$ towards $Y$. The resistance of unknown resistor is ___ $\Omega$.

Five positive charges each having charge $q$ are placed at the vertices of a regular pentagon as shown in the figure. The electric potential $V$ and the electric field $\vec{E}$ at the center $O$ of the pentagon due to these five positive charges are

A simple pendulum has a bob with mass $m$ and charge $q$. The pendulum string has negligible mass. When a uniform and horizontal electric field $ \vec{E} $ is applied, the tension in the string changes. The final tension in the string, when pendulum attains an equilibrium position is _______.
($ g $: acceleration due to gravity)

A battery with EMF $E$ and internal resistance $r$ is connected across a resistance $R$. The power consumption in $R$ will be maximum when :