Answer:
[tex]\lambda'=\dfrac{1}{2}\times \lambda[/tex]
Explanation:
The number of oscillation per unit time is called frequency of a wave while the distance between two consecutive crests and the trough is called its wavelength.
The wavelength of a wave is given by :
[tex]\lambda=\dfrac{v}{f}[/tex]
If frequency is doubled, f' = 2f
[tex]\lambda'=\dfrac{v}{f'}[/tex]
[tex]\lambda'=\dfrac{v}{2f}[/tex]
[tex]\lambda'=\dfrac{1}{2}\times \dfrac{v}{f}[/tex]
[tex]\lambda'=\dfrac{1}{2}\times \lambda[/tex]
So, when the frequency is doubled the wavelength of a wave on the string becomes half.