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

a. de Broglie wavelength, `lambda=(h)/(p) therefore p=(h)/(lambda)`
`K.E_("electron")=(p^(2))/(2m_(e ))=(h^(2))/(2m_(e )lambda^(2))`
b. `K.E_("neutron")=(h^(2))/(2m_(n)lambda^(2))`