SPECTRUM2

Mass of an atom of neon-22, m

= 21.9914u

= 3.82 X 10-26 kg

In quantum physics, the de Broglie wavelength is defined as

入 = h / p

where 入 is the de Broglie wavelength

h is Planck constant, h = 6.63 X 10-34 Js

p is the momentum of the particle

So, 3.27 X 10-12 = 6.63 X 10-34 / p

Momentum, p = 2.03 X 10-22 kgms-1

Momentum, p = mv

So, speed of the atom, v = 2.03 X 10-22 / 3.82 X 10-26

= 5.31 X 103 ms-2

As this speed is much lower than speed of light, so the relativistic effect can be ignored.

K.E. of the atom

= 1/2 mv2

= 1/2 (3.82 X 10-26)(5.31 X 103)2

= 5.38 X 10-19 J

= 3.36 eV