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For under certain conditions the chemical atoms emit light waves of a specific length or oscillation frequency - their familiar characteristic spectra - and these can come in the form of electromagnetic waves only from accelerated electric quanta.
因为在某些条件下，化学原子发出特定长度或振荡频率的光波——它们熟悉的特征光谱——而这些光波只能以电磁波的形式从加速的电量子中发出。