Electric fields and charges practice · Medium

The ratio of Coulomb's electrostatic force to the gravitational force between an electron and a proton separated by some distance is $2.4 \times 10^{39}$. The ratio of the proportionality constant, $K=\frac{1}{4 \pi \varepsilon_0}$ to the Gravitational constant $G$ is nearly

(Given that the charge of the proton and electron each $=1.6 \times 10^{-19} \mathrm{C}$, the mass of the electron $=9.11 \times 10^{-31} \mathrm{~kg}$, the mass of the proton $=1.67 \times 10^{-27} \mathrm{~kg}$)

The electric charge always resides:

If the charge on an object is halved then electric field becomes:

Assertion: At a point in space, the electric field points towards north. In the region, surrounding this point the rate of change of potential will be zero along the east and west.

Reason: Electric field due to a charge is the space around the charge.

Consider two concentric spherical surface $S_1$ with radius $a$ and $S_2$ within radius $2a$, both centeredon the origin. There is a charger $+ q$ at the origin, and no other charges. Compare the flux $\phi 1$ through $S_1$ with the flux $\phi 2$ through $S_2$

Given below are two statements
Statement-I: A point charge is brought in an electric field. The value of electric field at a point near to the charge may increase if the charge is positive.
Statement-II: An electric dipole is placed in a non-uniform electric field. The net electric force on the dipole will not be zero.
Choose the correct answer from the options given below

A body of mass M and charge q is connected to a spring of spring constant k. It is oscillating along x-direction about its equilibrium position, taken to be at x = 0, with an amplitude A. An electric field E is applied along the x-direction. Which of the following statements is correct?

A sphere encloses an electric dipole with charge $\pm 3 \times 10^{-6} \mathrm{C}.$ What is the total electric flux across the sphere?

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

If same charge $q$ is placed inside a sphere and cube hacing
radius 1 m and side 2 m respectively. What will be the ratio of
flux passing through them?

An electron is placed at the centre of a conducting sphere of radius $0.2\,\,$ metre having a charge $5 \times {10^{ - 2}}$ coulomb. The force on the electron

Point charge $5 q$ is placed inside a cube at centre, then electrostatic flux passing through one face of cube is

The force of repulsion between two electrons at a certain distance is $F$. The force between two protons separated by the same distance is: $\left(m_p=1836 {m}_e\right)$

Which of the following items is used in the
household wirings to prevent accidental fire in
case of short circuit?

The magnitude of electric field $E$ in the annular region of a charged cylindrical capacitor

A charge having $e/m$ equal to ${10^8}\,\,\,c/kg$ and with velocity $3 \times {10^5}\,\,\,m/s$ enters into a uniform magnetic field $B = 0.4\,\,\,{\text{tesla}}$ at an angle $30^\circ$ with direction of field. The radius of curvature will be

The electric charge in uniform motion
produces

When a proton is accelerated through $1V,$ then its kinetic energy 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 $\mathrm{x - axis}$ :-

If there is only one type of charge in the universe, then

Which of the following is incorrect regarding electrostatic field?

The law, governing the force between electric charge is known as

Assertion: If a conductor is given charge then no excess inner charge appears

Reason: Electric field inside conductor is zero

Assertion:- If more electric field lines leave a Gaussian surface than those which enter into it, then the net charge enclosed by that surface will be positive.
Reason:- If the net flux passing through a Gaussian surface is zero, then the net charge enclosed by that surface will be zero.