Catching up with the Imam in Ruku` after forgetting and sitting to perform Sujud

Q 4: We offered the Zhuhr (Noon) Prayer in congregation at school, and in the second Rak‘ah (unit of Prayer) when saying the Takbir ("Allahu Akbar [Allah is the Greatest]") before the Ruku‘ (bowing), I performed Sujud (prostration) instead of Ruku‘ while the rest were performing Ruku‘. When I noticed this, I stood up and performed Ruku‘. (Part No. 6; Page No. 45

A: You did the right thing when you performed Ruku‘ (bowing) in place of which you mistakenly made Sujud (prostration) and then you followed the Imam (the one who leads congregational Prayer); this is what you were obligated to do in this case. The repetition of the Salah was not necessary, because your first Salah was valid.May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.