Electric fields and charges practice · Mixed difficulty

The Gaussian surface for calculating the electric field due to a charge distribution is

The magnitude of the electric field due to a point charge object at a distance of 4.0 m is 9 N/C. From the same
charged object the electric field of magnitude, $16\frac{N}{C}$ will be at a distance of

Assertion (A): If two spherical conductors of different radii have the same surface charge densities, then their electric field intensities will be equal.
Reason (R): Surface charge density $= \frac{{\mathrm{Total}\,\,\mathrm{charge}}}{{\mathrm{area}}}$

Law stating that “force is directly proportional to product of charges and inversely proportional to square of separation between them” is called

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

A hemisphere is uniformly charged positively. The electric field at a point on a diameter away from the centre is directed

A charge $+ q$ is fixed to each of three corners of a square on the empty corner a charge $Q$ is placed such that there is no net electrostatic force acting is no net electrostatic force acting on the diagonally opposite charge. Then

The electrostatic force between two point charges is directly proportional to the

One of the following is not a property of field lines

A charge $q$ is placed on a solid metallic object of irregular shape. Charge $q$ will distribute itself.

Identify the WRONG statement

Two charges are at distance d apart in air. Coulomb force between them is F. If a dielectric material of dielectric
constant K is placed between them, the Coulomb force now becomes

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

Statement-1: If equal charge is put uniformly on a surface of two identical plates one of metal and other non-metal, then electric field in front of metal plate will be more.
Statement-2: Electric field in front of non-metal sheet is $\frac{\sigma}{2 \varepsilon_0}$ where $\sigma$ is the surface charge density.

Two conducting spheres of radii ${R_1}$ and ${R_2}$ having charges ${Q_1}$ and ${Q_2}$ respectively are connected to each other. There is

Compared to a similarly charged sphere, a charged conical conductor loses its charge due to

An electron and a proton are at a distance of $4\mathop A\limits^ \circ .$ The moment of this dipole [in $c-m$] will be

Assertion(A): If a bob of a simple pendulum is kept in a horizontal electric field, its period of oscillation will remain same.

Reason(R): If bob is charged and kept in horizontal electric field, then the time period will be decreased.

Two point charges are kept in air with certain separation between them. The force between them is $F_1$, if half of the space between the charges is filled with a medium of dielectric constant 4 and the force between them is $F_2$, if $\frac{1}{3}$rd of the space between the charges is filled with dielectric of dielectric constant 9. Then $F_1 / F_2$ is

Let$P\left( r \right) = \frac{Q}{{\pi {R^4}}}r$ be the charge density distribution for a solid sphere of radius $R$ and total charge $Q.$. For a point $'p'$ inside the sphere at distance ${r_1}$ from the centre of the sphere, the magnitude of electric field is

The dielectric constant K of an insulator cannot be:

The distance between a proton and electron both having a charge $1.6 \times {10^{ - 19}}coulomb,$ , of a hydrogen atom is ${10^{ - 10}}metre.$. The value of intensity of electric field produced on electron due to proton will be

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

The dielectric constant K of an insulator can be:

Assertion: A charge particle is released from rest in magnetic field then it will move in circular path.
Reason: Work done by magnetic field is non zero.

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

Electric lines of force:

Force of attraction between two point charges $Q$ and $-Q$ separated by $d\;meter$ is ${F_e}$. When these charges are placed on two identical spheres of radius $R = 0.3d$ whose centres and $d\;meter$ apart, the force of attraction between them is

An electron of mass $m$ and charge $e$ is accelerated from rest through a potential difference $V$ in vacuum. The final speed of the electron will be

The electrostatic force $\left(\overrightarrow{\mathrm{F}}_1\right)$ and magnetic force $\left(\overrightarrow{\mathrm{F}}_2\right)$ acting on a charge $\mathrm{q}$ moving with velocity $\mathrm{v}$ can be written: