For what kinetic energy of neutron will the associated de Broglie wavelength be `1.40 xx 10^(-10)m`? The mass of neutron is `1.675 xx 10^(-27) kg and h = 6.63 xx 10^(-34) J.s`

Explanation

If m be the mass and K be the kinetic energy of neutron, the de Broglie wavelength associated with it is given by,
`lamda = (h)/(sqrt(2mK))`
or `K = (h^(2))/(2mlamda^(2)) = ((6.63 xx 10^(-34))^(2))/(2 xx 1.675 xx 10^(-27) xx (1.40 xx 10^(-10))^(2))`
`= 6.69 xx 10^(-21)J`