An oscilloscope with a screen containing 10 horizontal divisions displays a sinusoidal wave, as shown in the diagram.
The time-base control of the oscilloscope is initially set to 20 μs div−120\,\mu\text{s}\text{ div}^{-1}20μs div−1.
The frequency of the input wave is then tripled, and the time-base control is changed to 8.0 μs div−18.0\,\mu\text{s}\text{ div}^{-1}8.0μs div−1.
How many complete cycles of the new wave are now displayed on the screen?
111
333
666
181818