How did Coulomb find the law of value of electric force between two point charges ?
How did Coulomb find the law of value of electric force between two point charges ?
Coulomb supposed the charge on a metallic sphere is $q$. If the sphere is put in contact with an identical uncharged sphere, the charge will spread over the two spheres. By symmetry the charge on each sphere will be $\frac{q}{2}$.
Repeating this process we can get charges $\frac{q}{2}, \frac{q}{4}$ etc.
Spheres are obtained with pairs of electric charges of $\frac{q}{2}, \frac{q}{4}, \frac{q}{8}, \ldots$ by repeating this process.
Coulomb varied the distance for a fixed pair of charges and measured the force for different separations. Then he gave relation,
$\mathrm{F} \propto \frac{1}{r^{2}} \quad \ldots$ $(1)$
He then varied the charges in pairs, keeping the distance fixed for each pair. Comparing forces for different pairs of charges at different distances, Coulomb gave the relation
$\mathrm{F} \propto q_{1} q_{2}$
... $(2)$
Thus, the electric force between two electric charges, $\mathrm{F} \propto \frac{q_{1} q_{2}}{r^{2}}$
$\therefore \mathrm{F}=k \frac{q_{1} q_{2}}{r^{2}}$ where $k$ is coulombian constant.
Similar Questions
Two identical metallic spheres $A$ and $B$ when placed at certain distance in air repel each other with a force of $F$. Another identical uncharged sphere $C$ is first placed in contact with $A$ and then in contact with $B$ and finally placed at midpoint between spheres $A$ and $B$. The force experienced by sphere $C$ will be.
Two identical metallic spheres $A$ and $B$ when placed at certain distance in air repel each other with a force of $F$. Another identical uncharged sphere $C$ is first placed in contact with $A$ and then in contact with $B$ and finally placed at midpoint between spheres $A$ and $B$. The force experienced by sphere $C$ will be.
- [JEE MAIN 2022]
What is the net force on a $Cl^{-}$ placed at the centre of the bcc structure of $CsCl$
What is the net force on a $Cl^{-}$ placed at the centre of the bcc structure of $CsCl$
- [AIIMS 2004]
The electrostatic force of interaction between an uniformly charged rod having total charge $Q$ and length $L$ and a point charge $q$ as shown in figure is
The electrostatic force of interaction between an uniformly charged rod having total charge $Q$ and length $L$ and a point charge $q$ as shown in figure is
Why Coulomb’s law is associated with Newton’s $3^{rd}$ law ?
Why Coulomb’s law is associated with Newton’s $3^{rd}$ law ?
Two spherical conductors $B$ and $C$ having equal radii and carrying equal charges in them repel each other with a force $F$ when kept apart at some distance. A third spherical conductor having same radius as that of $B$ but uncharged is brought in contact with $B$, then brought in contact with $C$ and finally removed away from both. The new force of repulsion between $B$ and $C$ is
Two spherical conductors $B$ and $C$ having equal radii and carrying equal charges in them repel each other with a force $F$ when kept apart at some distance. A third spherical conductor having same radius as that of $B$ but uncharged is brought in contact with $B$, then brought in contact with $C$ and finally removed away from both. The new force of repulsion between $B$ and $C$ is
- [AIEEE 2004]