When $0.50\,\text{Å}$ X-rays strike a material, the photoelectrons from the K-shell are observed to move in a circle of radius $23\,\text{mm}$ in a magnetic field of $2 \times 10^{-2}\,\text{T}$ acting perpendicularly to the direction of emission of photoelectrons. What is the binding energy of K-shell electrons?