Question

The fast moving neutron has wave associated with it, whose Broglie wavelength is 2 x 10-12m. Find phase velocity, group velocity and kinetic energy. (Given mass of neutron 1.67 x 10-27kg).​

Answer 1

Answer:

The  De Broglie wavelength of the neutron is =2.327×10−12m.

Kinetic energy of the neutron, K=150eV

=150×1.6×10−19

=2.4×10−19J

Mass of a neutron, me=1.675×10−27kg

The relation that gives the kinetic energy of neutron is:.

K=21mev2

mev=Kme

De-Broglie wavelength of the neutron is given as;

λ=mevh

λ=2Kmeh

The wavelength of the neutron is inversely proportional to the square root of its mass. So, there will be a decrease in wavelength with increase in mass and vice versa.

∴λ=2×2.4×10−17×1.675×10−276.6×10−34

=2.327×10−12m

So, the neutron beam of the same energy (150eV) will not be suitable.

(b) 

Room temperature, T=270C=27+