如图所示,平板MN上方有足够大的匀强磁场区域,磁场方向垂直纸面向里,质子(
![](https://math.21cnjy.com/MathMLToImage?mml=%3Cmath+xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F1998%2FMath%2FMathML%22%3E%3Cmrow%3E%3Cmsubsup%3E%3Cmrow%3E%3C%2Fmrow%3E%3Cmtext%3E1%3C%2Fmtext%3E%3Cmtext%3E1%3C%2Fmtext%3E%3C%2Fmsubsup%3E%3Cmtext%3EH%3C%2Fmtext%3E%3C%2Fmrow%3E%3C%2Fmath%3E)
)和氘核(
![](https://math.21cnjy.com/MathMLToImage?mml=%3Cmath+xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F1998%2FMath%2FMathML%22%3E%3Cmrow%3E%3Cmsubsup%3E%3Cmrow%3E%3C%2Fmrow%3E%3Cmtext%3E1%3C%2Fmtext%3E%3Cmtext%3E2%3C%2Fmtext%3E%3C%2Fmsubsup%3E%3Cmtext%3EH%3C%2Fmtext%3E%3C%2Fmrow%3E%3C%2Fmath%3E)
)从静止开始,经过同一个加速电场加速后,从平板上的小孔O先后射入匀强磁场,速度方向与平板MN夹角均为
![](https://math.21cnjy.com/MathMLToImage?mml=%3Cmath+xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F1998%2FMath%2FMathML%22%3E%3Cmi%3E%CE%B8%3C%2Fmi%3E%3C%2Fmath%3E)
(0<
![](https://math.21cnjy.com/MathMLToImage?mml=%3Cmath+xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F1998%2FMath%2FMathML%22%3E%3Cmi%3E%CE%B8%3C%2Fmi%3E%3C%2Fmath%3E)
<
![](https://math.21cnjy.com/MathMLToImage?mml=%3Cmath+xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F1998%2FMath%2FMathML%22%3E%3Cmi%3E%CF%80%3C%2Fmi%3E%3C%2Fmath%3E)
),整个装置放在真空中,且不计重力,不考虑两个粒子之间的相互作用。质子打到平板MN上的位置到小孔的距离为s,则( )
- A、质子和氘核在磁场中运动的时间之比为2:1
- B、保持其他量不变,当
时,氘核打到平板MN的位置离O点最远 - C、氘核到小孔的距离为
![](https://math.21cnjy.com/MathMLToImage?mml=%3Cmath+xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F1998%2FMath%2FMathML%22%3E%3Cmrow%3E%3Cmsqrt%3E%3Cmn%3E2%3C%2Fmn%3E%3C%2Fmsqrt%3E%3Cmi%3Es%3C%2Fmi%3E%3C%2Fmrow%3E%3C%2Fmath%3E)
- D、保持其他量不变,加速电场的电压加倍,质子到小孔的距离变为2s