the mass of an electron is `9.1 xx 10^(-31) ` kg . If its K.E. is ` 3.0xx 10^(-25) J`. Calculate its wavelength .

Explanation

`K.E. =1/2 mv^2=3.0 xx 10^(-25) J`
`v=((2 xx 3.0 xx 10^(-25))/(m))^1/2`
`=(2 xx 3.0 xx 10^(-25))/(9.1 xx 10^(-31))^(1/2)`
`=8.12 xx 10^(2) ms^(-1)`
Wavelength of the electron is given by
`lambda=h/(mv)=(6.626 xx 10^(-34))/(9.1 xx 10^(-31) xx 8.12 xx 10^2)`
`=8.967 xx 10^(-7)m`
=8967 A