Question

If the K_α radiation of Mo (Z = 42) has a wavelength of 0.71 Å the wavelength of the corresponding radiation for Cu (Z = 29) is –

• A. 1 Å
• B. 2 Å
• C. 1.52 Å
• D. 1.25 Å

Answer 1

Answer: (C)

1.52 Å

Answer 2

Moseley's law

$\sqrt { v } \propto \mathrm { Z } - 1$

ν ∝ (Z – 1)²

$\frac { \lambda _ { \mathrm { C } } } { \lambda _ { \mathrm { M } } }$=

λ_C = 0.71 Ч $\frac { 41 ^ { 2 } } { 28 ^ { 2 } }$ = 1.52 Å