Wavelength of the characteristic X-ray of iron and potassium are and respectively

PHYSICS · Subjective · A Level · Physics · Particles and radiation · Particles and radiation

Problem

Wavelength of the

K_\alpha

characteristic X-ray of iron and potassium are

1.931 \times 10^{-8}

and

3.737 \times 10^{-8} \text{ cm}

respectively. What is the atomic number and name of the element for which characteristic

K_\alpha

wavelength is

2.289 \times 10^{-8} \text{ cm}