Which of the following are compounds? Cu Fe H KF NaCl Ag Si H2O HCl

NaCl, H2O, HCl, and KF

15 m

Explanation:

We'll begin by calculating the speed of the wave. This can be obtained as follow:

Time = 5 s

Distance = 15 m

Speed =?

Speed = distance / time

Speed = 15 / 5

Speed = 3 m/s

Finally, we shall determine the distance between the crests of the wave. This can be obtained as follow:

Speed (v) = 3 m/s

Frequency (f) = 0.2 Hz

Distance between the crest (λ) =?

v = λf

3 = λ × 0.2

Divide both side by 0.2

λ = 3 / 0.2

λ = 15 m

Therefore, the distance between the crests of the wave is 15 m