6 The wavelength of a matter wave given by 
λ =ph
  has physical
significance; its phase velocity  vp has no physical significance However,
the group velocity of the matter wave is physically meaningful and
equals the velocity of the particle Physical
Symbol
Dimensions
Unit
Remarks
Quantity
Planck’s
h
[ML2T –1]
J s
E = hn
constant
Stopping
V0
[ML2T –3A–1]
V
e V0= Kmax
potential
Work
f0
[ML2T –2]
J; eV
Kmax = E –f0
function
Threshold
n0
[T –1]
Hz
n0 = f0/h
frequency
de Broglie
l
[L]
m
= h/p
wavelength
EXERCISES
11