If the kinetic energy of an electron is `4.55 xx 10^(-25)J`, find its wavelength (Planck's cosntant, `h = 6.625 xx 10^(-34) kgm^(2)s^(-1), m = 9.1 xx 10^(-31)kg`).

Explanation

`"KE of electron, "1//2mv^(2)=4.55xx10^(-25)J`.
`"Mass of electron, m"=9.1xx10^(-31)kg`
`v^(2)=(2xxKE)/(m)=(2xx4.55xx10^(-25)J)/(9.1xx10^(-31)kg)rArr v^(2)=10^(6)m^(2)s^(-2)`
`"Velocity of electron, v"=sqrt(10^(6))=10^(3)ms^(-1)`
`therefore"    Wave length, "lambda=(6.625xx10^(-34)Lgm^(2)s^(-1))/(9.1xx10^(-31)kgxx10^(3)ms^(-1))`
`therefore"   Wave length of electron "=lambda=728nm.`