Electric fields and charges practice · Medium

Two point charges $Q$ each are placed at a distance $d$ apart. A third point charge $q$ is placed at a distance $x$ from mid-point on the perpendicular bisector. The value of $x$ at which charge $q$ will experience the maximum Coulombs force is :

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

For a uniformly charged ring of radius $R,$ the electric field on its axis has the largest magnitude at a distance $h$ from its centre. Then, value of $h$ is

If a unit positive charge is taken from one point to another over an equipotential surface, then

The maximum electric field that a dielectric medium of a capacitor can withstand without break
down (of its insulating property) is called its :

Force acting upon a charged particle kept between the plates of a charged condenser is $F.$ If one plate of the condenser is removed, then the force acting on the same particle will become

A sphere of radius R has a uniform distribution of electric charge (q) in its volume. At a distance x from its centre, the electric field (at $x = \frac{R}{2}$) will be

Statement-I: A charge $q$ is lying at the centre of the line joining two similar charges $Q$ each. The system will be in equilibrium if $q=Q / 4$

Statement-II: For $Q$ to be in equilibrium, sum of the forces on $Q$ due to rest of the two charges must zero.

Charge ${q_2}$ of mass $m$ revolves around a stationary charge ${q_1}$ in a circular orbit of radius $r$ The orbital periodic time of ${q_2}$ would be

Assertion (A): The basic difference between magnetic lines of force and electric lines of force is electric lines of force are discontinuous and magnetic lines of force are continuous.
Reason (R): Magnetic lines of force exist in a magnet but no electric lines of force exists in a charged body.

The bob of simple pendulum is hanging vertically down from a fixed identical bob by means of string of length $l$. If both bobs are charged with a charge with a charge $q$ each, time period of the pendulum is (ignore the radii of the bobs)

Which of the following is deflected by electric field

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

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 $\mathrm{x - axis}$ :-

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

Dielectric constant for metal is

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?

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 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

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

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

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

The force per unit charge is known as_____.