The magneto-optic and optical properties of evaporated and sputtered Ag wer
e studied experimentally and theoretically. An apparent Kerr effect near 3.
9 eV was observed at room temperature. It was found to originate from the s
mall off-diagonal term of dielectric function tensor,induced by the free el
ectron movement under an applied magnetic field. The special optical proper
ties near 3.9 eV due to the strong plasma absorption affect the line shape
of the spectrum. The simulations,based on the classic Drude model,show the
effective electron mass m* = 0.8m(0). This provides a new method to experim
entally determine the effective electron mass and other parameters.