A force $F$ acts between sodium and chlorine ions of salt (sodium chloride) when put $1\,cm$ 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 $1\,cm$ apart is
A$\frac{F}{K}$
B$\frac{{FK}}{{{\varepsilon _0}}}$
C$\frac{F}{{K{\varepsilon _0}}}$
D$\frac{{F{\varepsilon _0}}}{K}$
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A$\frac{F}{K}$
a (a) When put $1$ $cm$ apart in air, the force between $Na$ and $Cl$ ions = $F$. When put in water, the force between $Na$ and $Cl$ ions $ = \frac{F}{K}$
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