Question

Two fixed charges 4Q (positive) and Q (negative) are located at A and B, the distance AB being 3 m.

(A) The point P where the resultant field due to both is zero is on AB outside AB. 

(B) The point P where the resultant field due to both is zero is on AB inside AB. 

(C) If a positive charge is placed at P and displaced slightly along AB it will execute oscillation 

(D) If a negative charge is placed at P and displaced slightly along AB it will execute oscillations.

Answer 1

Correct Option (A, D)
Explanation:

The resultant electric field will be zero at point closer to B and outside AB (by analysing directions of field and magnitudes)

If a positive charge is placed at P and distributed, the positive charge either goes towards, -Q or moves away from –Q but won’t oscillate

(unstable equilibrium) while negative charge oscillate