Question

Figure 1 shows a wave movement during one second. What is the frequency of the wave

A)2 hertz
B)2 meters/second
C)0.5 second
D)1 hertz

Answer 1

This is 2 hertz.  You can mark out 2 full wavelengths in the second of time.

Answer 2

2 hertz, as explained previously- I'm afraid m/s is a completely different measurement