Question

Suppose that the molybdenum (Z = 42) target in the X-ray tube is replaced by a silver (Z = 47) target. Do (a) the cutoff wavelength 10 and , (b) the wavelengths of the Ka X-ray photon increase, decrease, or remain the same? Assume that the voltage across the tube is constant and is sufficient to produce characteristic X-ray from both the targets. Provide a reason for each answer.

Answer 1

volatge supplied is needed here.

iam assung this to 45k V = 45000 V

then Cut off wavelength Lmin = hc/eV

Lmin = 6.623*10^-34 * 3*10^8/(1.6*10^-19 * 45000)

Lmin = 0.275 Armstrong units

---------------------

Molybdmin emits Kalpa line

ni= 2 and nf = 1

Mo atomic no. = 42

Wavenumber of Kalpha = R(Z-1)^2(1/nf^2 -1/ni^2)

Vkalphs = 1.097 *10^7 *(42-1)^2 (1/1-1/4)

Valpha = 1.38 *10^10 m^-1

Wavelengt L of K alpha = 0.725 A

---------------------

for Silver Z = 47

Vkalphs = 1.097 *10^7 *(47-1)^2 (1/1-1/4)

Valpha = 1.74 *10^10 m^-1

Wavelengt L of K alpha = 0.574 A