Calculate the energy of the neutron , if it's wavelength is 1 `A^@` ?

Explanation

`lambda=h/sqrt(2mE)` where E is the energy of the neutron.
`E=h^2/sqrt(2mlambda^2) = ((6.62xx10^-34)^2)/(2xx1.67xx10^-27xx(10^-10)^2)=1.301xx10^-20`
`E=(1.301xx10^-20)/(1.6xx10^-19)=0.081eV`