Question

Two charges are placed a certain distance apart in air. If a glass slab is introduced between them, the force between them will

• A. increase
• B. decrease
• C. remain the same
• D. become zero

Answer 1

The correct option is B decrease

Two charges are placed a certain distance apart in air. If a glass slab is introduced between them, the force between them will decreases.

$F=\frac{1}{4\pi {\epsilon }_0}\frac{q^2}{r^2}\left(invacuum\right)$

But if medium is inserted:

$F^{\prime }=\frac{1}{4\pi {\epsilon }_0{\epsilon }_m}\frac{q^2}{r^2}\left(inmedium\right)F^{\prime }=\frac{F}{{\epsilon }_m}$