20180228

Physics quiz question: direction of total electric field

Physics 205B Quiz 3, spring semester 2014
Cuesta College, San Luis Obispo, CA

Cf. Giambattista/Richardson/Richardson, Physics, 2/e, Problem 16.33

Two point charges are held at fixed locations. The total electric field at x = +0.5 cm is directed to the:
(A) left.
(B) right.
(C) (There is no direction, as the electric field is zero.)
(D) (Not enough information is given.)

Correct answer (highlight to unhide): (A)

The electric field vectors due to the –2.0 nC source charge are shown at right, where they all point in towards the negative source charge. (The magnitudes of these electric field vectors are not quite to scale, but do get smaller with increasing distance from the –2.0 nC source charge).

The electric field vectors due to the +8.0 nC source charge are shown at right, where they all point out away from the positive source charge. (The magnitudes of these electric field vectors are not quite to scale, but do get smaller with increasing distance from the +8.0 nC source charge, and are proportionally larger than the electric field vectors of the less –2.0 nC source charge).

The total electric field at x = +0.5 cm due to both source charges would be the vector addition of the individual electric field vectors at that location, as they point in the same direction (to the left).

Sections 30882, 30883
Exam code: quiz03cDvD
(No results compiled)

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