Question

Crystal diffraction experiments can be performed using X-rays, or electrons accelerated through appropriate voltage. Which probe has greater energy? (For quantitative comparison, take the wavelength of the probe equal to 1 Å, which is of the order of interatomic spacing in the lattice) (me= 9.11 × 10⁻³¹ kg).

Answer 1

An X-ray probe has a greater energy than an electron probe for the same wavelength. Wavelength of light emitted from the probe, λ = 1 Å = 10⁻¹⁰ m
Mass of an electron, me = 9.11 × 10⁻³¹ kg
Planck’s constant, h = 6.6 × 10⁻³⁴ Js
Charge on an electron, e = 1.6 × 10⁻¹⁹ C

The kinetic energy of the electron is given as:

Hence, a photon has a greater energy than an electron for the same wavelength.