Question

12.
Two charges are at distance (d) apart in air. Coulomb
force between them is F. If a dielectric material of
dielectric constant (K) is placed between them, the
coulomb force now becomes.
(A) FIK
(B) FK
(C) FIKZ
(D) KF​

Answer 1

Answer:

F/K

Explanation:

According to the given question,

Initial force = F

Or the force in air/vacuum

dielectric constant = K

Dielectric constant: it's the ratio of force in vacuum to medium. It's also known as relative permittivity.

Vacuum or air has the highest relative permittivity.

Final force = F"

or the force in dielectric medium

We know,

The relation between Force of air or vacuum and medium is

• K = F/F"

Now,

• F" = F/K ans.

Thus it means that force of dielectric medium will be reduced by 1/K times of vacuum force.

And force is maximum in vacuum or air.

Answer 2

12. Two charges are at distance d apart in air. Coulomb force between them is F. If a dielectric material of dielectric constant K is placed between them, the coulomb force now becomes F/K.

Option (A) is correct

• Given,
• d is the distance between 2 charges.
• F is the Coulomb force between the 2 charges.
• K is the dielectric constant of a dielectric material placed between 2 charges.
• Now, let,
• F' be the new Coulomb force.
• as, we know that,
• Force ∝ 1/K

• we have, the new Coulomb force

• F' = F/K