Question

The wavelength of an X-ray beam is $10{\text{A}}^{\circ }$. The mass of a fictitious particle having the same energy as that of the X – ray photons is $\frac{x}{3}h\text{kg}$. The value of $x$ is _______.

Answer 1

Given wavelength of an X-ray beam $=10A^{\circ }$
$E=\frac{hc}{\lambda }=m{c}^2$
$m=\frac{h}{c\lambda }$ will be the mass of a particle having the same energy

The mass of a fictitious particle having the same energy as that of the X-ray photons $=\frac{x}{3}h\text{kg}$

$\frac{xh}{3}=\frac{h}{c\lambda }$
$x=\frac{3}{c\lambda }=\frac{3}{3\times {10}^8\times 10\times {10}^{-10}}$
$x=10$