Electric fields and charges practice · Mixed difficulty

Assertion:- Electric force is the reason for existence of molecules.
Reason:- At atomic level electric force is the most effective force or strongest force.

Electric field strength due to a point charge of $10\,\,\mu C$ at a distance of 80 cm from the charge is $[N/C]$

Assertion: A line of force has sudden breaks.

Reason: An electrostatic line of force is a continuous curve.

Two charges each ‘Q’ are released when the distance between is ‘d’. Then velocity of each charge of mass ‘m’ each when the distance between them is ‘2d’ is

A point charge $q$ is placed at origin. Let $\overrightarrow{\mathrm{E}}_{\mathrm{A}}, \overrightarrow{\mathrm{E}}_{\mathrm{B}}$ and $\overrightarrow{\mathrm{E}}_{\mathrm{C}}$ be the electric field at three points $\mathrm{A}(1,2,3), \mathrm{B}(1,1,-1)$ and $\mathrm{C}(2,2,2)$ due to charge q. Then

Statement-1: Two point charges $+Q$ and $-Q$ are fixed at point $A(+a, 0,0)$ and point $B(-a, 0,0)$ respectively. Then the magnitude of electric flux due to electric field of either point charge through infinite $y-z$ plane (that is $x=0$ plane) is less than magnitude of net electric flux due to electric field of both charges through that plane ($x=0$ plane).
Statement-2: The magnitude of net electric flux through a surface due to a system of point charges is equal to sum of magnitude of electric flux through that surface due to each of the point charge of the system.

Eight dipoles of charges of magnitude $e$ are placed inside a cube. The total electric flux coming out of the cube will be

A free alpha particle and a free proton are separated by distance of $10^{-10} \mathrm{~m}$ and are released. The kinetic energy of alpha particle when at infinite separation is

Identify the wrong statement in the following. Coulomb’s law correctly describes the electric force that

Assertion: With the help of Gauss's theorem we can find electric field at any point.

Reason: Gauss's theorem can be applied for any type of charge distribution.

A positively charged rod is brought near to a nonconducting object. The rod is attracted to the object. From this observation we can't predict whether the object is charged or uncharged. Some additional experiments have been performed to identify whether the object is charged or uncharged, these experiments with their observations and conclusions drawn are given. Select the option in which conclusion drawn is correct.

Assertion: If a charged particle is released from rest in a region of uniform electric and magnetic fields parallel to each other, it will move in a straight line.
Reason: The electric field exerts no force on the particle but the magnetic field does.

A cube of metal is given a positive charge $Q.$ For the above system, which of the following statements is true

Assertion:- Charge is invariant.
Reason:- Charge does not depend on speed or frame of reference.

Two conducting spheres of radii $r_1$ and $r_2$ are charged to equal surface charge density. The ratio of electric fields just outside the surface is:

When a body is charged by conduction, its mass

The angle between the electric lines of force and the equipotential surface is:

The charge on an electron was calculated by:

A hollow cylinder of length $L$ and radius $R$ having surface area $A$ is placed horizontally with its axis parallel to an external field ${E}.$ The electric flux through the surface of the cylinder is

A charged spherical conductor has a surface density of $0.7 \mathrm{~Cm}^{-2}$. When its charge is increased by $0.44 \mathrm{~C}$, the charge density changes by $0.14 \mathrm{Cm}^{-2}$. Find the radius of the sphere and initial charge on it.

A particle of $'m'$ and charge $'q'$ is accelerated through a potential difference of $V\;volt,$ its energy will be

A cylinder of radius R and length L is placed in the uniform electric field E to the cylinder axis. The total flux for the surface of the cylinder is given by

Two identical charged spheres are suspended by strings of equal lengths. The stings make an angle of ${30^\mathrm{o}}$ with each other. When suspended in a liquid of density $0.8g\;c{m^{ - 3}},$ the angle remains the same. If density of the material of the sphere is $1.6g\;c{m^{ - 3}},$ the dielectric constant of the liquid is

Assertion:- Under electrostatic conditions net electric field inside a solid conductor will be zero.
Reason:- Under electrostatic conditions there will be no free electrons inside a conductor.

A non-uniformly charged sphere has charge density given by $\rho=\frac{a^2}{R}$ where '$a$' is a constant. '$r$' is the distance from the centre and '$R$' is the radius of the sphere. Then the total charge inside the sphere is proportional to

Assuming that the charge on an atom is distributed uniformly in a sphere of radius $10^{-10} \mathrm{~m}$, what will be the electric field at the surface of the gold atom? For gold, $\mathrm{Z}=79$.

Which of the following is the correct statement of Gauss law for electrostatics in a region of charge distribution in free space

An electron of mass '$m$' charge '$e$' falls through a distance '$h$' metre in a uniform electric field '$E$'. Then, time of fall:

The electric flux from a cube of edge $l$ is $\phi$ in an enclosed charge. If the edge of the cube is made $\frac{2}{3} l$ and the charge enclosed in the cube is doubled, then the electric flux value will be

Units of electric flux are