This was because the experiment showed that a substance could emit radiation even while it was not exposed to light.
we have,
wavelenght=c/f
where c= 3×10^8 m/s
f=6.3×10^12 s^-1
so wavelength=(3×10^8)/(6.3×10^12)
=0.476×10^-4 m
<span>In the electron cloud model, the denser areas represent that there is a great probability that a good number of electrons are ganged up or crowded in that area. The electrons affect the density of some parts of the electron cloud when they condense in those locations.</span>