Calculate the wavelength of an electron moving with a velocity fo ` 2. 05 xx 10^7 ms^(-1)`.

Explanation

` lambda = h/( m u)`
`"Mass of electron in motion" (m')= m/( sqrt ( 1 - ( u/c)^2))`
`"Mass of electron " m'=(9.11 xx 10^(-31))/(sqrt(1-((2.05 xx 10^(7))/(3.0 xx 10^(8)))^(2)))`
` = 9. 16 xx 10^(-31)`
` :. lambda = ( 6.626 xx 10^(-34))/(9. 16 xx 10 ^(31) xx 2. 05 xx 10^7 ) = 3 . 52 xx 1^(-11) m`.