本题目来源于试卷: Motion of charged particle and Velocity selector and Mass spectrometer，类别为 美国物理杯赛(Physics Bowl)
[单选题]
94.30: The conventioultt-vg ;d xt16 ql(hj5d3- xdnal current I in a long straight wire flows in hpw)g itc287,mf7(.mw)v7ak cd2sk y hp)boothe upward direction as shown in the figure. (Electron flow is downward.) At the instant a proton of charge +e ibhm2k (.ov7k7fw, cy7t g)2cow hasp)i)d8pms a distance R from the wire and heading directly toward it, the force on the proton is:
A. $\frac{\mu_0\:I^2}{2\pi}$ toward the wire.
B. $\frac{\mu_0\:I^2L}{2\pi\:R}$ upward (in the same direction as I).
C. $\frac{\mu_0\:I^2L}{2\pi\:R}$ downward (in the opposite direction to I).
D. ev$\frac{\mu_0\:I}{2\pi\:R}$ upward (in the same direction as I).
E. ev$\frac{\mu_0\:I}{2\pi\:R}$ downward (in the opposite direction to I).
参考答案: E
本题详细解析:
暂无
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