Question

94. A force Facts between sodium and chlorine ions of salt (sodium chloride) when put icmapart
in air. The permittivity of air and dielectric constant of water are cand krespectively. When a piece
of salt is put in water electrical force acting between sodium and chlorine ions 1cm apart is​

Answer 1

Given :

Distance between sodium and chlorine ions = 1cm

Permittivity of air = ε₀

Dielectric constant of water = k

To Find :

The electrical force acting between sodium and chlorine ions

Solution :

• The force of attraction between two charged particles is

               $F=\frac{1}{4\pi \epsilon_{0}} \frac{q_{1}q_{2} }{r^{2} }$

• Force between charged particles in medium of dielectric constant k is

               $F=\frac{1}{4\pi \epsilon_{0}k} \frac{q_{1}q_{2} }{r^{2} }$

               $F=\frac{1}{4\pi \epsilon_{0}k} \frac{q_{1}q_{2} }{1^{2} }$

               $F=\frac{q_{1} q_{2} }{4\pi \epsilon_{0}k}$

The force between sodium and chloride ions in water is   $F=\frac{q_{1} q_{2} }{4\pi \epsilon_{0}k}N$.