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$2.5 \textrm{ J}$

# Giancoli 6th Edition, Chapter 17, Problem 16

(3:46)

Hi thesouthportschool, the negative sign in $W= -qV$ that you're used to seeing is the work done by the electric field. Since, in this question, we're asked to find the work done by an external force, the external force is applying a force in the opposite direction to that of the electric field. For this reason the work done by the external force has a sign opposite to that of the electric field, which means $W_{ext} = qV$ with no negative sign.