Nuclear & Particle Physics - X-rays

A beam of electrons is accelerated through a potential difference of 25 kV in an X-ray tube. The continuous X-ray spectrum emitted by the target of the tube will have a short wavelength limit of most nearly

A. 0.1 Å
B. 0.5 Å
C. 2 Å
D. 25 Å
E. 50 Å

(GR9277 #80)

Solution:

Energy: E = pc
Wavelength: λ = h/p = hc/E

E = 25 kV
h = 4.14 × 10⁻¹⁵ eV second
c = 3 × 10⁸ m/s
hc = 1.24 × 10⁻⁶ eVm

→ λ = ^{1.24 × 10−6}/_{25 × 10³}  = ½ × 10⁻¹⁰ m = 0.5 Å

Answer: B