Q. A force $F$ acts between sodium and chlorine ions of salt (sodium chloride) when put $1cm$ apart in air. The permittivity of air and dielectric constant of water are $\varepsilon_{0}$ and $K$ respectively. When a piece of salt is put in water electrical force acting between sodium and chlorine ions $1cm$ apart is
A) $\frac{F}{K}$
B) $\frac{FK}{\varepsilon_{0}}$
C) $\frac{F}{K\varepsilon_{0}}$
D) $\frac{F\varepsilon_{0}}{K}$
Explanation
(a) When put $1cm\ $apart in air, the force between $Na$ and $Cl$ ions $= F.$ When put in water , the force between $Na$ and $Cl$ ions $= \frac{F}{R}$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.