a light source that utilizes light emitting diodes that emit white light is disclosed . the diodes are mounted on an elongate member having at least two surfaces upon which the light emitting diodes are mounted . the elongate member is thermally conductive and is utilized to cool the light emitting diodes . in the illustrative embodiment , the elongate member is a tubular member through which a heat transfer medium flows . a cooling or fluid movement device coupled with the elongate thermally conductive member enhances cooling of the light emitting diodes .