Silver metal. Protected silver has greater optical reflectivity than aluminium at all wavelengths longer than ~450 nm. At wavelengths shorter than 450 nm, silver's reflectivity is inferior to that of aluminium and drops to zero near 310 nm. Very high electrical and thermal conductivity is common to the elements in group 11, because their single s electron is free and does not interact with the filled d subshell, as such interactions (which occur in the preceding transition metals) lower electron mobility. The electrical conductivity of silver is the greatest of all metals, greater even than copper, but it is not widely
Electrical resistivity and conductivity inside the conductor. Conductivity is the inverse (reciprocal) of resistivity. Here, it is given by: For example, rubber is a material with large "ρ" and small "σ"—because even a very large electric field in rubber makes almost no current flow through it. On the other hand, copper is a material with small "ρ" and large "σ"—because even a small electric field pulls a lot of current through it. As shown below, this expression simplifies to a single number when the electric field and current density are constant in the material. When the resistivity of a material has a directional component,