The wavelength of light from the spectral emission line of sodium is 589 nm. Find the kinetic energy at which
(a) an electron, and
(b) a neutron, would have the same de Broglie wavelength.

Explanation

`lambda=(h)/(p)=(h)/(sqrt(2m_(n)K.E))impliesK.E.=(h^(2))/(2m_(n)(lambda)^(2))`
`=((6.62xx10^(-34))^(2))/(2xx1.67xx10^(-27)xx(589xx10^(-9))^(2))=3.78xx10^(-28)J`