Question

A thin insulator rod is placed between two unlike point charges $+q_1$ and $q_2$ . For this situation tick the correct alternative (s)

• A. The total force acting on charge $+q_1$ will increase
• B. The total force acting on charge $-q_2$ will increase
• C. The total force acting on charge $-q_2$ will decrease
• D. The force acting on charge $+q_1$ due to $-q_2$ will remain same

Answer 1

The correct option is D The force acting on charge $+q_1$ due to $-q_2$ will remain same

Without rod the force between two charges is $F=\frac{q_1(-q_2)}{4\pi {ϵ}_{0}r}$ where ${ϵ}_0=$ permittivity of free space

When rod inserted between charges , the force $F^{\prime }=\frac{q_1(-q_2)}{4\pi ϵ}$ where $ϵ=$ permittivity of insulator medium.

Since ${ϵ}_0>ϵ$ so $F^{\prime }>F$

According to Coulomb's law the force of attraction on both charges will equal.