Question

Two very small spheres having charge +Q, and -Q face
each other at a certain distance between them. If a
dielectric having dielectric constant K inserted
between them then electrostatic force between them
Increase
Decrease
Remains same
Becomes zero​

Answer 1

Given:

Two very small spheres having charge +Q and -Q face each other at a certain distance between them.

To find:

Change in force when a dielectric material is kept between them?

Calculation:

Now, in initial conditions, the electrostatic force in between the charges will be :

$F = \dfrac{1}{4\pi \epsilon_{0}} \times \dfrac{Q \times Q}{ {d}^{2} }$

But now, a dielectric material of DIELECTRIC CONSTANT 'K' is placed in between the charges.

So, new electrostatic force is:

$F_{2} = \dfrac{1}{4\pi \epsilon_{0}K} \times \dfrac{Q \times Q}{ {d}^{2} }$

Now, comparing the Equations:

$\implies \: F_{2} = \dfrac{F}{K}$

• Since value of K > 1 , depending on the medium.

$\implies \: F_{2} < F$

So, force decreases. (OPTION 2)

Answer 2

Answer:

as columb force constant it remains same