For a x-ray if it's wavelength is `10 A^@` & mass of a particle having same energy and same wavelength as x-ray is `(xh)/3` where h is plank's constant then value of x is

Answer

A

Explanation

Given wavelength of an x-ray beam = 10 Å
` :. E = (hc)/lambda =mc^(2)`
The mass of a fictitious particle having the same energy as that of the x - ray photons = `(xh)/3 ` kg
`(xh)/3 =h/(clambda)`
`x = 3/(clambda)= 3/(3xx10^(8)xx10xx10^(-10))`
x=10 .