A new contactless method of determining the carrier lifetime in semiconductors is presented. It uses the dependence of the magnetic field evoked by photoelectromagnetic current in an illuminated semiconductor placed in an external magnetic field on the frequency of chopping the illumination intensity. This method was used to determine the electron lifetime in p-type crystalline silicon. It is suitable for rapid and simple inspection of a semiconductor wafer for laboratory and industrial purposes. The using of this method in investigations of superlattices and multi-quantum wells is proposed.