In fig, two particles, each of charge -q are arranged symmetrically about the y-axis, each producing an electric field at point P on the y-axis.
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(a) Are the magnitudes of the fields at P equal?
(b) Is each electric field directed towards or away form the charge producing it ?
(c ) Is the magnitude of the net electric field at P equal to the sum of the magnitudes E of the two field vectors (is it equal to 2E)?
(d) Do the x-components of those two field vectors add or cancel?
(e ) Do their y-components add or cancel?
(f) Is the diretion of the net field at P that of the canceling components or the adding components?
(g) What is the direction of the net field?

Explanation

(a) yes.
(b) toward
(c ) No, it is less than 2E.
(d) Cancel
(e ) Add
(f) Adding components
(g) Negative y.