比较了平衡电压的静态法与动态法,证明动态法才是合理的测量方法。使用通用大学物理密立根油滴实验装置,通过手机录像、逐帧读取的方法减小了时间误差,采用螺旋测微器测量了极板间距,利用测微尺校准了下落距离,结合室内温湿度测量和腔室升温测量对空气黏度系数相关的电量误差进行了温湿度校正,并采用改进的动态法测量了平衡电压。分析表明上述手段的综合运用才保证了测量的准确性。油滴参数的选择范围得以拓展:平衡电压降至40 V,下落时间降至7 s。
The dynamic method was demonstrated to be the rational method for the measurement of the balancing voltage by comparison with the static method.Experiments were done with apparatus commonly used in Millikan’s oil drop experiment of college physics.Time error was reduced through cell phone video recording and frame-by-frame reading.The distance between the two plate electrodes were measured with a screw micrometer.The falling height of oil drop was calibrated with a stage micrometer.The charge error originated from the viscosity coefficient of air was corrected according to the room temperature and humidity and the increased temperature of the oil test chamber above it.And the balancing voltage was measured with the improved dynamic method.Analyses demonstrated that it was only the synthesis utilization of the above methods that guaranteed the accuracy of the measurements.The choice ranges of parameters were expanded to 40 V for the balancing voltage and 7 s for the falling time.
Physical Experiment of College
Millikan’s oil drop experiment
temperature and humidity related correction