On a 20 MHz oscilloscope as those used in class, the knob of the time sweep rate shows for the fastest setting the mark of 0.2 microseconds per major division in horizontal direction on the screen. How many full periods of a 5 MHz periodic signal will be observed in one major horizontal division
As the fastest setting for the time sweep rate (which defines what is displayed horizontally) is set at 0.2 μsec per major horizontal division on the screen, we can see exactly 0.2 sec of the signal in each division.
As the period is equal to the time for one cycle, and is equal to the time displayed per div (0.2 μsec), we will be able to see one full cycle in one major horizontal division.