American Journal of Physics vol:76 issue:7 pages:626-629
We discuss several important issues concerning the use of a lock-in amplifier and the experimental procedure that need to be addressed to obtain accurate measurements of the Faraday rotation using ac magnetic fields. Our study was conducted on BK7 glass. We show that if electronic interference is avoided and the dependence of the signal on the average light intensity is taken into account, an accurate value of the Verdet constant for thin samples can be determined. (C) 2008 American Association of Physics Teachers.