  Concentrated electric field and its energy in materials, containing
nanofibers, are discussed. It is shown that the electric field in the vicinity
of the end of a fiber is proportional to the external applied field and to the
fiber length, whilst it is inversely proportional to the fiber diameter.
Specific electrostatic energy of a fiber in a sample under the action of
external applied field is calculated. This energy appears to be negative and
proportional to the ratio of the fiber length to its diameter. This means that
longer fibers are more stable than the shorter ones.
