Determining the velocity of light in air from the path and transit time of a short light pulse

In the experiment P5.6.2.1, the path of the light pulses is varied once, and the change in the transit time is measured with the oscilloscope. The velocity of light can then be calculated as quotient of the change in the transit distance and the change in the transit time. Alternatively, the total transit time of the light pulses can be measured in absolute terms using a reference pulse. In this case, the velocity of light can be calculated as quotient of the transit distance and the transit time. A quartz-controlled oscilloscope signal can be displayed on the instrument simultaneously with the measuring pulse in order to calibrate timing. Time measurement is then independent of the time base of the oscilloscope.