comparison of material sizes

Hi,
Why all the material dimensions are measured with respect to wavelength. Wat is the need of measuring with wavelength.

At all frequencies, interconnections,loose bits of cable etc. exhibit some impedance. If the length and frequency of the signal are in the correct ratio what was a piece of wire will now act like a tuned circuit, which could reject the working frequency. In lots of areas where the frequency is low, such as audio, unless you are using kMs of lead length the effect can be ignored. As the frequency is raised these side effects become major effects and are used such as in aerials. you could say that this track must be 300/4 * Fworking M long or its quarter wavelength.
Frank