Answer:
The frequency decreases
Explanation:
In a wave, the relationship between wavelength and frequency is given by
[tex]f=\frac{v}{\lambda}[/tex]
where
f is the wave frequency
v is the wave speed
[tex]\lambda[/tex] is the wavelength of the wave
In this problem, the wavelength of the wave is made longer (increased). From the formula above, we notice that the frequency is inversely proportional to the wavelength: therefore, as the wavelength increases, the frequency will decrease.