Coulomb's Law

Two protons move parallel to each other, keeping distance r between them, both moving with same velocity $\overrightarrow{\text{V}}$. Then the ratio of the electric and magnetic force of interaction between them is

What is C in physics Coulombs law ?

A charge $+q$ is situated at a distance '$d$' away from both the sides of a grounded conducting '$L$' shaped sheet as shown in the figure.

The force acting on the charge $+q$ is

The force of attraction between two charges $8 \mathrm{\mu C}$ and $-4 \mathrm{\mu C}$ is $0.2 \mathrm{N}$. Find the distance of separation (in metre):

 As per Coulomb's law, the force of attraction or repulsion between two point charges is directly proportional to the

The Dielectric constant of a medium is the ratio of the permittivity of the substance to the permittivity of free space

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

Three particles of charges $1\times {10}^{-8} \mathrm{C}, 8.0\times {10}^{-8} \mathrm{C}$ and $27\times {10}^{-8} \mathrm{C}$ are kept fixed on the $x$-axis at point $x=10 \mathrm{cm}, 20 \mathrm{cm}$ and $30 \mathrm{cm}$ respectively. The magnitude of the electric force acting on a $1 \mathrm{C}$ charge placed at $x=0.$ (Assume $\frac{1}{4\pi {\epsilon }_0}=9\times {10}^9 \mathrm{N} {\mathrm{C}}^{-2} {\mathrm{m}}^2$)

When distance between two-point charges is increased by $10\%$, the force of interaction

Two point charges $+\mathrm{ }3\mathrm{ }\mathrm{\mu }\mathrm{C}$ and $+\mathrm{ }8\mathrm{ }\mathrm{\mu }\mathrm{C}$ repel each other with a force of $40\mathrm{ }\mathrm{N}$. If a charge of $–5\mathrm{ }\mathrm{\mu }\mathrm{C}$ is added to each of them, then the magnitude of the force between them and nature of force is/are:

The force between two small charged spheres having charges of $1\times {10}^{-7} \mathrm{C}$ and $2\times {10}^{-7} \mathrm{C}$ placed $20 \mathrm{cm}$ apart in air is _____.

Two point charges A and B, having charges $+\mathrm{Q}$ and $-\mathrm{Q}$ respectively, are placed at certain distance apart and force acting between them is $\mathrm{F}$. If  $25\mathrm{\%}$ charge of A is transferred to B, then the force between the charges becomes

Two point charges $+\mathrm{ }3\mathrm{ }\mathrm{\mu }\mathrm{C}$ and $+\mathrm{ }8\mathrm{ }\mathrm{\mu }\mathrm{C}$ repel each other with a force of $40\mathrm{ }\mathrm{N}$. If a charge of $–5\mathrm{ }\mathrm{\mu }\mathrm{C}$ is added to each of them, then the force between them will become:

Ravi rubs a plastic comb on his dry hair and then places it near a water stream. The stream of water is seen to bend towards the plastic comb. Which force is behind this event?

The separation between two point charges $q_{\mathit{1}}$ and $q_{\mathit{2}}$ is $3 \mathrm{m}$. The sum of the two charges is $20 \mathrm{\mu C}$ and they repel each other by a force of $0.075 \mathrm{N}$. Find the value of the two charges.

Two small identical balls each of mass and charge $q$ are suspended same point by silk cords (each cord is of length $\mathcal{l}$) as shown in fig. separation between charges is $\mathrm{x}$ and angle between cords $(2\mathrm{\theta } \approx {10}^{°})$. Calculate the value of $\mathrm{x}$ assuming system to be in equilibrium.

Two identical spherical conductors $\mathrm{B}$and $\mathrm{C}$ carry equal like charges and repel each other by a force $F$ when placed at a certain distance apart. Another identical conductor which is uncharged is made into contact with $\mathrm{B}$ then with $\mathrm{C}$ and removed away from $\mathrm{B}$ and $\mathrm{C}$. Find the new force acting between $\mathrm{B}$ and $\mathrm{C}$.

Two identical metallic spheres are charged with $+10\mathrm{\mu C}$and $-20\mathrm{\mu C}$. If they are brought into contact and then kept at the same separation as earlier, then find the ratio of forces in final and initial situations.