The mass of an electron is `9.1xx10^(-31)kg`. If its K.E. is `3.0xx10^(-25) J`, calculate its wavelength

Explanation

`K.E.=1/2 mv^(2)`
`:. V=sqrt((2 K.E.)/m)=sqrt((2xx3.0xx10^(-25) J)/(9.1xx10^(-31) kg))=812 ms^(-1)" "(1 J=1 kg m^(2) s^(-2))`
By de Broglie equation, `lambda=h/(mv)=(6.626xx10^(-34) Js)/((9.1xx10^(-31) kg)(812 ms^(-1)))=8.967xx10^(-7) m=8967 Å`