Question

Till, what distance coulomb’s law is applied ?
A. Atomic distance 10-11m
B. Nuclear distance 10-15m
C. Long distance of 1 Km
D. For all distances

Answer 1

Hint:- Coulomb’s law is given by the formula :
$F = \dfrac{{k{Q_1}{Q_2}}}{{{R^2}}}$ (F is the force Q1 and Q2 are charges ,R is the distance between charges, k is the constant of proportionality)
Formula for Coulomb’s law gives us the force acting between two charges .
Now let us conclude more points which will prove the distance of Coulomb law application.

Complete step-by-step solution :Coulomb’s law states that, two point charges which are stationary with respect to each other exerts a force on each other and this force is directly proportional to the product of charges and inversely proportional to the square of the distance between them. The mathematical representation is given as :
$F = \dfrac{{k{Q_1}{Q_2}}}{{{R^2}}}$
Form the definition of Coulomb’s law, we have concluded two points :
The particles must be point charges.
The particle must be stationary with respect to one another.
In options we are given:
Atomic distance: it is the distance between two atoms of an element. From here we can observe that atoms will remain stationary only electrons revolve inside the atoms overall atom is stationary and it is also a point size particle. So, we can say that it obeys Coulomb’s law.
Nuclear distance : nuclear distance is the distance between the nuclei of two atoms .We know that nucleus of an atom is also stationary and is also a point charge .Thus coulombs’ law is applicable .
Long distance of 1 Km : yes 1 Km long distance is also applicable with stationary and point charge particles .
Thus we can conclude that coulomb’s law is applicable for all distances, option 4 is correct.

Note:-
Coulomb’s is applicable for all distances given in the options because those distances are in a certain specified range .From the formula of the Coulomb’s law we can say that as distance increases upto an infinite range then the force will tend to almost zero.
Therefore Coulomb’s law must be defined within a certain range of distance.