2）在外加磁场的作用下，氢质子发生的运动是( ) A: precession B: rotating C: vibration D: swing
2）在外加磁场的作用下，氢质子发生的运动是( ) A: precession B: rotating C: vibration D: swing
A sidereal day is shorter than a solar day. This difference is due to（）. A: irregularities in the daily rotational rate of the Sun B: the space motion of the solar system C: the precession of the equinoxes D: the use of different reference point
A sidereal day is shorter than a solar day. This difference is due to（）. A: irregularities in the daily rotational rate of the Sun B: the space motion of the solar system C: the precession of the equinoxes D: the use of different reference point
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