Electric Field & Field Lines
The three charges q/2, q and q/2 are placed at the corners A, B and C of a square of side 'a' as shown in figure. The magnitude of electric field (E) at the corner D of the square, is:

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Answer: (a)
- Let . and ( each, distance ) give each, at right angles.
- Their resultant along diagonal :
- (, distance ) gives , also along away from .
- So the answer is (a).