Coulomb's Law
Coulomb's Law: Overview
This Topic covers sub-topics such as Coulomb's Law, Coulomb's Law in Vector Form, Permittivity of Vacuum, Permittivity of a Medium and, Electrostatic Force between Two Charges in Vacuum
Important Questions on Coulomb's Law
Two fixed point charges units are separated by a distance ‘a’. Where should the third point charge be placed for it to be in equilibrium?
How does the coulomb force between two point charges depend upon the dielectric constant of the intervening medium?
and are placed at and respectively. The force on the second is of the form
Two point charges and repel each other with a force of . If a charge is added to each of these charges, the force would be:
The centres of two identical small conducting spheres are apart. They carry charges of opposite kind and attract each other with a force . When they are connected by a conducting thin wire they repel each other with a force What is the ratio of the magnitude of charges carried by the spheres initially?
A charge is placed at each of the two opposite corners of a square. A charge is placed at each of the other two corners. If the resultant force on is zero, then
Electric charges of and are placed in air at the corners and respectively of an equilateral triangle having length of each side The resultant force on the charge at is
Two conducting spheres of radii and are separated by a distance of in free space. If the spheres are charged to same potential of each, the force of repulsion between them is
A charged ball hangs from a silk thread which makes an angle with a large charged conducting sheet as shown in the figure. The surface charge density of the sheet is proportional to

A charge exerts force on a second charge If a third charge is brought near, the force of exerted on
As per Coulomb's law, the force of attraction or repulsion between two point charges is directly proportional to the
The electrostatic force acting on a charge q lying at a distance of on axial position from centre of a dipole is now if this distance is made double, then find the new value of force. Assume that separation between two charge of the dipole is less than
The ratio of and so as to make the system in equilibrium is :

Two point charges are kept in air with a separation between them. The force between them is , if half of the space between the charges is filled with a dielectric of dielectric constant and the force between them is , if of the space between the charges is filled with dielectric of dielectric constant. Then is
When distance between two-point charges is increased by , the force of interaction
A charge is placed at the centre of the line joining two equal charges The system of the three charges will be in equilibrium if is equal to
Below the fixed end of the insulating horizontal thread, at a distance equal to the length of the thread, there is a fixed charge which has the same charge as the charge of the small body of mass at the end of the thread as shown in the figure.
The body is released. When it is at the lowest position the angle between the thread and the horizontal is . The mass of the moving body is closest to:

In the figure shown, is a fixed charge and (of mass ) is given a velocity perpendicular to line At this moment, the radius of curvature of the resultant path of is

The force between two small charged spheres having charges of and placed apart in air is _____.
Two point charges A and B, having charges and respectively, are placed at certain distance apart and force acting between them is . If charge of A is transferred to B, then the force between the charges becomes
