試題詳解

8. Four point charges of +0.500 μC, +1.50 μC, -1.00 μC, and -0.500 μC are randomly distributed on a ring. If the electric potential at the center of the ring due to the +0.500 μC charge alone is 4.5 × 10⁴ V, what is the total electric potential at the center due to all four charges?
(A) 0
(B) -4.5 × 10⁴ V
(C) 4.5 × 10⁴ V
(D) 9.0 × 10⁴ V
(E) 18.0 × 10⁴ V