Is Sajdah necessary when one hears an aayat of Sajdah being recited on the radio or a recording?

Answer

Sajdah Tilaawat is not incumbent when listening to such an aayat on a recording of any type. The tilaawat (recitation) of a recording is not a valid Tilaawat in terms of the Shariah. It is like the recitation of a parrot.