n = ρ z N a A

(electrons/m3)

Density (ρ)

(g/cm3)

I

(eV)

Material

3.52987 × 1029

1.070E+00

74.3

0.54709

Eye Lens

(ICRU-44)

3.34713 × 1029

1.000E+00

75.0

0.55508

Water