Electric fields and charges practice · Mixed difficulty

The phenomenon used in the designing of T.V. cables is

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 force on $q$ charge is placed in an uniform electric field $E$ will be

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.

Point charges $+ 4q,\,\, - q\;\mathrm{ and } + 4q$ are kept on the $\mathrm{x - axis}$ at points $x = 0,\,\,x = a\mathrm{ \,\,and}\,\,\,\mathrm{ }x = 2a$ respectively, for displacement along $\mathrm{x - axis}$ :-

Suppose we have a large number of indentical particles, very small in size. Any pair of them at $10 \mathrm{~cm}$ separation repel with a force of $3 \times 10^{-10} \mathrm{~N}$. If one particle of them is at $10 \mathrm{~cm}$ from a group of $\mathrm{n}$ others, how strongly do you expect it to be repelled?

Statement-1: A device used to measure $\overrightarrow{{E}}$ is located a some distance from a fixed point charge. In this situation, the device measures $E_0$ as the magnitude of electric field intensity. Now an uncharged conducting sphere with a very small hole is lowered by an insulating thread so that it surrounds the point charge. Now, the reading of the device becomes zero.
Statement-2: Electrostatic shielding is the phenomenon in which inside of hollow conductor is shielded for outside electric field.

The electric field created by a point charge falls with distance $r$ from the point charge as

Dielectric constant for metal is

Two equal negative charges $-q$ are fixed at the points $(0, a)$ and $(0,-a)$ on the $y$-axis. A positive charge $Q$ is released from rest from the point $(2 a, 0 )$ on the $x$-axis. The charge will

During thunderstorm, it is advised to

An electric dipole is put in north-south direction in a sphere filled with water. Which statement is correct

A neutron, a proton and an electron are placed in a uniform electric field.

A ring of radius $r$ carries a charge $Q$ uniformly distributed over its length. A charge $q$ is placed at its centre will experience a force equal to

Electric charges under action of electric forces is called

Which of the following statement is correct?

A cubical Gaussian surface encloses 36 C of charge. The electric flux through each surface of cube is [in Wb]

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

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:

Two parallel metal plates having charges $+ Q$ and $- Q$ face each other at a certain distance between them. If the plates are now dipped in kerosene oil tank, the electric field between the plates will

Gauss’s law of electricity is given by

Force between two identical charges placed at a distance of $r$ in vacuum is $F$. Now a slab of dielectric of dielectric constant 4 is inserted between these two charges. If the thickness of the slab is $r/2,$ then the force between the charges will become

An electron enters in high potential region ${V_2}$ from lower potential region ${V_1}$ then its velocity

Assertion (A): Some charge is put at the centre of a conducting sphere. It will move to the surface of the sphere.

Reason (R): Conducting sphere has no free electrons at the centre.

Assertion: On bringing a positively charged rod near the uncharged conductor, the conductor gets attracted towards the rod.
Reason: The electric field on the surface of a conductor is directly proportional to the surface charge density at that point.

A charge of 10 C is placed at the centre of a spherical Gaussian surface of radius 20 cm. The flux through the surface is $\frac{1}{{{\varepsilon _0}}}$ times of $\left[ {N{m^2}/C} \right]$

A comb run through one’s dry hair attracts small bits of paper. This is due to

An electric field is given by $(6 \hat{i}+5 \hat{j}+3 \hat{k}) {N} / {C}$. The electric flux through a surface area $30 \hat{i} {~m}^2$ lying in ${YZ}$-plane (in ${SI}$ unit) is :

Statement-I: A positive point charge is brought in an electric field, the electric field at neary by point will increase

Statement-II: Electric field produced by charge may favour the existing electric filed

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