Question

The kinetic energy of an electron is `4.55 xx 10^(-25)J`. Calculate the wavelength .
`[h = 6.6 xx 10^(-34)Js`, mass of electron `= 9.1 xx 10^(-31)kg]`

Answer 1

`K.E = (1)/(2)mv^(2) = 4.55 xx 10^(-25)`
`=(1)/(2) xx 9.1 xx 10^(-31) xx v^(2) = 4.55 xx 10^(-25)`
`rArr v^(2) = (2 xx 4.55 xx 10^(-25))/(9.1 xx 10^(-31)) = 10^(6) rArr v = 10^(3) ms^(-1)`
Applying de Broglie equation
`lambda = (h)/(mv) = (6.6 xx 10^(-34))/(9.1 xx 10^(-31)xx 10^(3)) = 0.72 xx 10^(-6)m`