Understanding Forces Exerted by Charged Bodies

A charged body possesses an electric charge, which is a fundamental property of matter. When a charged body comes near another body, whether that body is also charged or is uncharged, a force acts between them. This force arises due to the presence of electric charges.

Identifying the Force Between Charged and Uncharged Bodies

Let's examine the types of forces listed in the options to determine which one describes the interaction between a charged body and another body (charged or uncharged).

• Muscular force: This is a contact force exerted by the muscles of a body. It is not related to electric charges.
• Centrifugal force: This is an apparent outward force felt by an object moving in a circular path, directed away from the center of rotation. It is an inertial force and is related to motion, not electric charges.
• Centripetal force: This is a real force that acts towards the center of a circular path, causing an object to move in a circle. It is also related to motion, not electric charges.
• Electrostatic force: This is the force exerted by a stationary electric charge on another stationary electric charge. It can be attractive or repulsive. Furthermore, a charged body can also exert an electrostatic force on an uncharged body through a phenomenon called electrostatic induction.

Based on these definitions, the force exerted by a charged body on another charged body or an uncharged body is the electrostatic force.

What is Electrostatic Force?

Electrostatic force is one of the fundamental forces in nature. It acts between objects that have an electric charge. The magnitude and direction of this force are described by Coulomb's Law for point charges:

\(F = k \frac{|q_1 q_2|}{r^2}\)

where:

• \(F\) is the magnitude of the electrostatic force between the two charges.
• \(q_1\) and \(q_2\) are the magnitudes of the charges.
• \(r\) is the distance between the centers of the two charges.
• \(k\) is Coulomb's constant (\(k \approx 8.9875 \times 10^9 \, \text{N} \cdot \text{m}^2/\text{C}^2\)).

This force is repulsive if the charges have the same sign (both positive or both negative) and attractive if the charges have opposite signs (one positive and one negative).

Electrostatic Force on an Uncharged Body (Electrostatic Induction)

When a charged body is brought near an uncharged body, it can cause a separation of charges within the uncharged body. For example, if a positively charged rod is brought near a neutral metal sphere, the free electrons in the sphere are attracted towards the rod, accumulating on the side closer to the rod. The side farther away will have a net positive charge. This process is called electrostatic induction. As a result, the closer side of the sphere has an induced charge opposite to that of the rod, and the farther side has an induced charge of the same type. Since the attractive force between the rod and the closer opposite charge is stronger than the repulsive force between the rod and the farther like charge (because the distance is smaller), there is a net attractive electrostatic force between the charged body and the initially uncharged body.

Therefore, a charged body exerts an electrostatic force on both charged and uncharged bodies.

Revision Table: Types of Forces

Additional Information on Electrostatics

• Electric Field: A charged body creates an electric field in the space around it. This electric field is the medium through which the electrostatic force is exerted on other charges or bodies.
• Types of Charges: There are two types of electric charges: positive and negative. Like charges repel, and unlike charges attract.
• Conductors and Insulators: Materials vary in how easily charges can move through them. Conductors allow charges to move freely, while insulators restrict charge movement. Electrostatic induction effects are more pronounced in conductors.