It's hard to tell from your questions, but it sounds like you're talking resonant lengths of wire for antennas. You're going to have to be a bit clearer phrasing your question.
This sounds like a school assignment too, which probably means it needs to be in the homework forum.
Electrical length is related to the wavelength of a signal propagating in a trasnmission line. It is also related to the properties of the materials and the geometry of the construction. Since wavelength times frequency is a constant we can see that electrical length changes as the frequency of the signal changes.