Electrostatic Force and Electric Field (id: b83dcd91a)

本题目来源于试卷: Electrostatic Force and Electric Field，类别为 美国物理杯赛(Physics Bowl)

[单选题]
94.39: A small objecandb f6jq 6bza7-( st6t wzh h7bvzm;04a ith charge q and weight mg is attached to one end of a string of length L. The other end is attached to a stationary support. The system is placed in a uniform horizont;4hbavmhz z0 7al electric field E, as shown in the accompanying figure. In the presence of the field, the string makes a constant angle q with the vertical. What is the sign and magnitude of q?

A. positive with magnitude mg/E
B. positive with magnitude mg tanθ/E
C. negative with magnitude mg/E
D. negative with magnitude mg tanθ /E
E. negative with magnitude E tanθ /mg


参考答案:  B


本题详细解析: 暂无

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