Question

Why the wave length decreases with the increases in speed of electron

Answer 1

Because the wavelength is inversely proportional to the speed....

Answer 2

As the speed of the electron increases, the electron's De Broglie wavelength decreases, described by the following equation as shown below : lemda = h/p, where lemda  is the wavelength, h is Planck's universal constant, and p is the momentum. ...

lemda = h/mv  

as we can see that lemda inversely propotional to speed of wave.

if speed increases wavelength decreases.

I hope it will be helpful .

thanks