Explanation:
Since, it is given that one hand completes 3.19 vibrations in 8.46 sec. Therefore, in one second the number of vibrations will be as follows.
[tex]\frac{3.19}{8.46}[/tex]
= 0.377 vibrations
Hence, frequency (f) = 0.38 Hz
Now, formula to calculate the speed is as follows.
v = [tex]f \times \lambda[/tex]
or, [tex]\lambda = \frac{v}{f}[/tex]
= [tex]\frac{0.6 cm/s}{0.38}[/tex]
= 1.57 cm
Thus, we can conclude that the wavelength is 1.57 cm.