Question

Two charged thermocol balls held close to each other move away from each other when they are released. Name the force which is responsible for this phenomenon.
${\text{A}}{\text{.}}$ Electrostatic force
${\text{B}}{\text{.}}$ Magnetic force
${\text{C}}{\text{.}}$ Gravitational force
${\text{D}}{\text{.}}$ Spring force

Answer 1

Hint: Here, we will proceed by stating Coulomb’s law. Then, we will write down the magnitude of the electrostatic force according to Coulomb’s law along with the direction of the electrostatic force acting between two like and unlike charges.

Complete step-by-step answer:

Coulomb’s law states that the electrostatic force between any two charged particles is directly proportional to the magnitudes of the charges of the charged particle and inversely proportional to the square of the distance.

According to Coulomb’s law, the magnitude of the electrostatic force acting between two charged particles having charges ${{\text{q}}_1}$ and ${{\text{q}}_2}$ separated through a distance of r is given by

${\text{F}} = \dfrac{{{\text{K}}{{\text{q}}_1}{{\text{q}}_2}}}{{{{\text{r}}^2}}}$ where F represents the magnitude of the electrostatic force, K denotes the Coulomb’s law constant, ${{\text{q}}_1}$ and ${{\text{q}}_2}$ represents the magnitude of the charges, r denotes the distance of separation between the charges

According to Coulomb’s law, the electrostatic force between two charges acts in such a way that it attracts the unlike charges (i.e., one positive charge and one negative charge) and repels the like charges (i.e., either both positive charges or both negative charges)
Here, we have two charged thermocol balls and they are held close to each other and due to this they are moving away from each other. This means that the charged thermocol balls are repelling each other which can only occur if they are bearing similar charges (by similar charges we mean that they are like charges i.e., both positive charges or both negative charges).

Therefore, electrostatic force is the force which is responsible for this phenomenon.
Hence, option A is correct.

Note: Electric charge is the property of objects which gives rise to the force observed. Electrical force also acts at a distance like gravitational force. Electrical forces are very high, much stronger than gravitational forces. There are two types of electric charge, unlike gravity, (whereas there is only one type of gravity i.e., gravity attracts only).