To find:
Change in the frequency if the wavelength is reduced by a factor of 4.
Explanation:
The speed of a wave is given by,
[tex]v=f\lambda[/tex]
Where f is the frequency and λ is the wavelength of the wave.
If the wavelength is reduced by a factor of 4, then,
[tex]\begin{gathered} v=f_n\frac{\lambda}{4} \\ \implies f\lambda=f_n\frac{\lambda}{4} \\ \implies f_n=4f \end{gathered}[/tex]
From above calculation, it is clear that the new frequency will be 4 times the old one.
Final answer:
Thus the correct answer is option D.
