Electric fields and charges practice · Medium

Given below are two statements:
Statement I: A time varying electric field is a source of changing magnetic field and vice-versa. Thus a disturbance in electric or magnetic field creates EM waves.
Statement II: In a material medium, the EM wave travels with speed $v = \frac{1}{{\sqrt {{\mu _0}{\varepsilon _0}} }}.$
In the light of the above statements, choose the correct answer from the options given below.

A conducting sphere of radius $5 \mathrm{~cm}$ has an unknown charge. The electric field at $10 \mathrm{~cm}$ from the centre of the sphere is $1.8 \times 10^3 \mathrm{~N} / \mathrm{C}$ and points radially inward. What is the net charge on the sphere?

Two infinite plane parallel sheets separated by a distance $d$ have equal and opposite uniform charge densities $\sigma .$ Electric field at a point between the sheets is

Choose the correct relation between polarization '$\text{P}$' and electric susceptibility '$\chi_{\mathrm{e}}$' of dielectric material. $(\text{E}=$ electric field)

A cube of side $b$ has a charge $q$ at each of its vertices. The electric field due to this charge distribution at the centre of this cube will be

According to Gauss’ Theorem, electric field of an infinitely long straight wire is proportional to

Assertion:- Charge given to a conductor appears on its surface.
Reason:- When charge appears on surface then potential energy of conductor becomes minimum.

A point charge of 1.8μC is at the centre of cubical Gaussian surface 55cm on edge. What is the net electric flux through the surface?

A long, hollow conducting cylinder is kept coaxially inside another long, hollow conducting cylinder of larger radius. Both the cylinders are initially electrically neutral.

Equipotential surfaces corresponding to electric field due to an infinitely large uniformly charged sheet are

A golden ornament has a charge of $+ {10^{ - 4}}\,\,{\text{coulombs}}.$ The number of electrons removed from the ornament is

Which of the following statements is not true about Gauss’ law?

Two charges, each of $5\,\,\mu c$ but opposite in sign, are placed 4cm apart. What is the value of electric field intensity at a point distance 4 cm from the mid-point on the axial line of the dipole?

If $\sigma$ is the surface charge density of the conductor then, mechanical force per unit area of a charged conductor is proportional to:

Two insulated charged metallic spheres '$P$' and '$Q$' of negligible radii have their centers separated by a distance of $60 \mathrm{~cm}.$ The mutual force of electrostatic repulsion if the charge on each $6 \times 10^{-7} \mathrm{C}$ is _______

Assertion: The coulomb force is the dominating force in the universe.

Reason: The coulomb force is stronger than the gravitational force.

A $100 \mathrm{~eV}$ electron is fired directly towards a large metal plate having surface charge density $-2 \times 10^6 \mathrm{~C} \mathrm{~m}^{-2}$. The distance from where the electron is projected so that just fails to strike the plate is

Two charged spheres of radii $10cm$ and $15cm$ are connected by a thin wire. No charge will flow, if they have

Two positive charges $Q_1$ and $Q_2$ are fixed at $A$ and $B$. A unit positive charge is taken from $A$ to $B$ along the line joining $A B$. The force experienced by unit charge

Statement-I: Acceleration of charged particle in non uniform electric field does not depend on veloicty of charged particle

Statement-II: charge is an invariant quantity, that is, amount of charge on particle doesn't depend on frame of referenced

The inward and outward electric flux for a closed surface in units of $N - {m^2}/C$ are respectively $8 \times {10^3}$ and $4 \times {10^3}$. Then the total charge inside the surface in S.I. units is (Where ${\varepsilon _0}$ = permittivity constant)

The ratio of the forces between two small spheres with constant charge $\left( a \right)$ in air $\left( b \right)$ in a medium of dielectric constant $K$ is

A body has a charge of $9.6 \times {10^{ - 20}}$ coulomb. It is

Top of the stratosphere has an electric field $E$ (in units of $V/m$) nearly equal to

If a proton is moved against the coulomb force
of an electric field, then

The scientist whose major contribution is
towards the measurement of electronic charge

Two charges placed in air repel each other by a force of ${10^{ - 4}}N.$ When oil is introduced between the charges, the force becomes $2.5 \times {10^{ - 5}}N.$ The dielectric constant of oil is

While taking off synthetic clothes, seeing a spark or
hearing a crackle, are due to

Assertion: Two identicalballs are charged by $q$. They are suspended from a common point by two insulating threads $l$ each. In equilibrium the angle between the threads is $180^{\circ}$. (Ignore gravity)

Reason: In equllibrium tension in the springs is $T=\frac{1}{4 \pi \varepsilon_0} \times \frac{q \cdot q}{l^2}$

Assertion:- An electric charge is fixed in free space which produces an electric field around it. No work is done in displacing another charge from its position to any other position.
Reason:- Electrostatic field is non conservative.