Question

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

Answer 1

From the figure given we can see that there are 2 waves produced or traveled after 1 second. The frequency of the wave is calculated by dividing the number of waves by time. From this given, the frequency is,
                                frequency = 2 waves / 1 s
                                frequency = 2/s 
                                frequency = 2 Hz

Answer 2

2 hertz is the answer