Question

In the arrangement shown in figure, the two point charges are in equilibrium. The infinite wire is fixed in the horizontal plane, and the two point charges are placed on above and the other below the wire.
Considering the gravitational effect of the earth, the nature of $q_1$ ane $q_2$ can be

• A. $q_1\to positive,q_2\to positive$
• B. $q_1\to positive,q_2\to negative$
• C. $q_1\to negative,q_2\to negative$
• D. $q_1\to negative,q_2\to positive$

Answer 1

Answer: (B), (C)

The correct options are
B $q_1\to positive,q_2\to negative$
C $q_1\to negative,q_2\to negative$

For positive $q_1$ and negative $q_2$ fbd is shown. It is clear from the fbd that system can in eqilibrium due to opposite forces acting on both charge particles.

Similarly negative $q_1$ and negative $q_2$ system can be in equilibrium.