In absence of viscosity, the amplitude of surface waves is said to
be inversely proportional to sqrt(r), where r is the distance from the
source. This will be the case if the width of the area of the
disturbance in water remains constant. But is it not more logical to
assume that the this width itself is proportional to the amplitude
of the waves at that location? Some assume that the disturbance
extends upto a distance of one wavelength into the water, i.e.,
constant. How can this be justified if the amplitude varies from
point to point?