SAT Subject Physics Practice Question 80: Answer and Explanation

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Question: 80

7. The potential at point A in an electric field is 10V higher than at point B. If a negative charge, q = –2 C, is moved from point A to point B, then the potential energy of this charge will

A. decrease by 20 J
B. decrease by 5 J
C. increase by 5 J
D. increase by 20 J
E. increase by 100 J

Correct Answer: D

Explanation:

7 D As we move from point A to point B, the potential decreases by 10 V, so ∆V = –10 V. Now, since ∆U = q ∆ V, we have ∆U = (–2 C)(–10 V) = +20 J.

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