The wavelength
of 200 eV electrons is about 0.87 Angstroms (0.87 x 10^{-10}
m)

**Rationale**

Using the same equation as in the previous question

Wavelength, λ ~ ( 150 / V )^{1/2}
Angstroms

and substituting V = 200 gives a wavelength of around 0.87 Angstroms .