本题目来源于试卷: Fields D.2 Electromagnetic Fields & Potential，类别为 IB物理学
[单选题]
Two charges separated by a d w:)*pk-afdgsd w8,mlm.ph3iistance r are placed in a m47 dnh8tm 9yvtedium with permittivity ϵ. The charges are then moved to air so that they have the same force between them as that in the medi 7mtydh t49n8vum.
What is the distance between the charges in air, knowing that $ϵ$=$ϵ_r$$ϵ_0$?
A. $ϵ_rr$
B. $\frac{r}{ϵ_r}$
C. $\frac{r}{\sqrt{ϵ_r}}$
D. $r\sqrt{ϵ_r}$
参考答案: D
本题详细解析:
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