Question

8. An element with atomic number Z=11 emits Ka X-ray of
wavelength a, then the atomic number of the element.
which emits Ką X-ray of wavelength 42 is:​

Answer 1

Answer:

As per question, 

given that atomic number of an element Z1=11

a wavelength of an elementλ1=λ

the atomic number of the second element Z2=?

a wavelenght of the second element λ2=4λ

According to Moseley's law v=a(z−b)

or v=a2(z−b)2

or λc=a2(z−b)2

∴λ2λ1=(z1−1)2(z2−1)2

∴4λλ=(11−1)2(z2−1)2

or (z2−1)2=25 or z2=6

So the atomic number of the second elementZ2=6