Question

Why is Coulomb's force (either attraction or repulsion) in vacuum always greater than Coulomb's force (either attraction or repulsion) in any medium ?
Please answer in such a way that I could write In exam for 2marks

Answer 1

Answer:

See below.

Explanation:

a) The Coulomb force depends on three quantities, namely, charge, distance and the permittivity of medium.

b) The Coulomb force is inversely proportional to the permittivity of the medium. It is given by,

$\dfrac {\varepsilon }{\varepsilon _{0}}=k$

Epsilon is the permittivity of the medium and epsilon zero is the absolute permittivity of vaccum.

c) In most cases, we consider that the expermient is being conducted in vaccum. Therefore we write,

$F=\dfrac {1}{4\pi \varepsilon _{0}}\dfrac {q_{1}q_{2}}{r^{2}}$

d) For any other medium like solids, liquids and gases, the relative permittivity is higher and hence the force is comparatively weaker than that in vaccum.