which is an eigenfunction of the momentum operator.
of: particles, in a stream of particles represented by the spatial wavefunction which is an eigenfunction of the momentum operator.
given that: the average number of particles per unit length is the constant 
and their velocity is obtained from the momentum, 
is: the net number crossing a fixed plane per unit time, i.e. 
[P11.1]
Copyright 1997, The Open University