Electric fields and charges practice · Mixed difficulty

Assertion: All the charges in a conductor get
distributed on whole of its outer surface.

Reason: In a dynamic system, charges try to
keep their potential energy minimum.

The surface charge density $\left( {\mathrm{in\;}C/{m^2}} \right)$ of the earth is about

If the electric field near the earth's surface be $300 \mathrm{~V} / \mathrm{m}$ directed downwards, then the surface density of charge on earth's surface is

A charge $Q$ is to be distributed on two conducting spheres. Find out values of charges on spheres so, that the repulsive force between them is maximum at fixed distance.

The force per unit charge is known as_____.

What is the magnitude of a point charge due to which the electric field 30cm away has the magnitude $2\;newton/coulomb$ $[1/4\pi {\varepsilon _0} = 9 \times {10^9}N{m^2}/{C^2}]$

Which of the following is false for electric lines
of force?

Assertion: The coulomb force is the dominating force in the universe.
Reason: The coulomb force is weaker than the gravitational force.

A charged bead is capable of sliding freely
through a string held vertically in tension. An
electric field is applied parallel to the string, so
that the bead stays at rest at middle of the
string. If the electric field is switched off
momentarily and switched on

A proton and an electron are placed in a uniform electric field then

Two spherical conductors A and B of radii 1mm and 2mm are separated by a distance of 5cm and are uniformly charged. If the spheres are connected by a conducting wire then in equilibrium condition, the ratio of the magnitude of the electric fields at the surfaces of spheres A and B is

The electric field in a region of space is given by $\overrightarrow E = 5\widehat i + 2\widehat j\,\,N{C^{ - 1}}$. The electric flux due to this field through an area $2{m^2}$ lying in the YZ plane in S.I. Units is

Assertion:- Electric field lines are always perpendicular to the surface of conductor.
Reason:-Electric field is always perpendicular to equipotential surface.

Assertion: In a region, where uniform electric field exists, the net charge within volume of any size is zero.

Reason: The electric flux within any closed surface in region of uniform electric field is zero.

If point charges $Q_1=2 \times 10^{-7} \mathrm{C}$ and $Q_2=3 \times 10^{-7} \mathrm{C}$ are at $30 \mathrm{~cm}$ separation, then find electrostatic force between them

A positive charge of $17.7 \mu \mathrm{C}$ is placed at the centre of a hollow sphere of radius $0.5 \mathrm{~m}$. Calculate the flux density through the surface of the sphere.

The electric field inside a spherical shell of uniform surface charge density is

Two spheres of copper of the same radii, one hollow and other solid, are charged to the same potential. The hollow sphere has

The force between two point charges placed in a material medium of dielectric constant $\varepsilon_\text{r}$ is $\text{F}.$ If the material is removed, then the force between them becomes

A conducting sphere of radius $R$, carrying charge $Q$, lies inside an uncharged conducting shell of radius $2R$. If they are joined by a metal wire,

(A) $Q/3$ amount of charge will flow from the sphere to the shell

(B) $2Q/3$ amount of charge will flow from the sphere to the shell

(C) $Q$ amount of charge will flow from the sphere to the shell

(D) amount of heat will be produced $K Q^2 / 4 R$

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

The intensity of electric field at the surface of conducting hollow sphere is $10\, \mathrm{NC}^{-1}$ and its radius is $10 \mathrm{~cm}$. The value of electric field at the centre of sphere is

Two identical conducting spheres carrying different charges attract each other with a force $F$ when placed in air medium at a distance $d$ apart. The spheres are brought into contact and then taken to their original positions. Now the two spheres repel each other with a force whose magnitude is equal to that of the initial attractive force. The ratio between initial charges on the spheres is

Electric charge between two bodies can be produced by

Consider $\overrightarrow {{E_1}} = x\hat i + \hat j$ and $\overrightarrow {{E_2}} = x{y^2}\hat i + {x^2}y\;\hat j;$ then

Select the correct statements. Coulomb's law correctly describes the electric force that:
(i) binds the electrons of an atom to its nucleus.
(ii) binds the protons and neutrons in the nucleus of an atom.
(iii) binds atoms together to form molecules.

A Gaussian sphere encloses an electric dipole within it. The total flux across the sphere is

A simple pendulum of period $T$ has a metal bob which is negatively charged. If it is allowed to oscillate above a positively charged metal plate, its period will

A proton and an electron are released from
an infinite distance apart and they get
attracted towards each other. Which of the
following statement about their kinetic
energy is true?

Assertion (A): Using Gauss law, it is possible to find the electric field at any point.
Reason (R): Gauss law is applicable for any type of charge distribution.