Steady-state deformation of a vesicle with a membrane of arbitrary con
ductance in an alternating electric field is discussed. A simple formu
la is obtained for the elongation modulus of the vesicle as a function
of the frequency of the applied field. The dependences of this modulu
s on the conditions in the medium and the membrane characteristics are
illustrated in detail. Experimental applicability to the extraction o
f information on the characteristics of a vesicle are discussed.