Is it obligatory for the congregant to recite the Fatiha in congregational prayer during the audible (jahr) rak'ahs, and if so, does the Imam recite the Fatiha silently and audibly in the same rak'ahs?

The preponderant view is that reciting Al-Fatihah is obligatory for the worshipper behind the imam (ma'mum) in both audible and silent prayers, based on the generality of the hadith: "There is no prayer for one who does not recite the Opening of the Book (Fatihat al-Kitab)," and his (peace be upon him) saying: "So do not do it, except for the Mother of the Qur'an, for there is no prayer for one who does not recite it." As for the verse: {And when the Qur'an is recited, listen to it and pay attention} and the hadith: "And when he (the imam) recites, then pay attention," these are general and have been specified by the hadiths on the obligation of reciting Al-Fatihah. It is permissible for the worshipper behind the imam to recite Al-Fatihah while the imam is reciting, and then to listen attentively. As for the imam, it is not prescribed for him to repeat Al-Fatihah.