It is wajib to listen to the Qur’an when it is being recited. When the Quran is prayed loudly in a gathering then it is obligatory for all present to listen-if the reason for the gathering is to pray the Quran, otherwise if only one listens then it is sufficient regardless if others are busy in their work. (Guniyyah, Fatawa-e-Radawiyyah, Bahar-e-Shariat).
Similarly it is Wajib to listen and answer the call of Azaan, even the recitation of the Quran should be stopped.
