→ mkcha:題目應該有錯P是別的物理量 被耍了Orz 07/05 02:42
11.An electron is launched(發射) with velocity v in a uniform magnetic field B
.the angle x between v and B is 0~90.As a result,the electron follows a
helix(螺旋線),its velocity vector v returning to its initial value in a
time interval of
(A)2pmvsinx/eB (B)2pmv/eB (C)2pm/eB (D)2pmvcosx/eB
題目就有點不懂
請問一下答案和所需的觀念
謝謝
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