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 distance*cqp hmt, swwsnf0;f h9;m58c r are placed in a me)3h4if8g0v4lm3+tiut n kfs q w81ee hiq1y 9ydium with permittivity ϵ. The charges are then moved to air so that they have the same force betf4vetw1etih3g nfqy 1 43uimliy0qkh89)+s8ween them as that in the medium.
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:
| 
