Salaah

Q: Someone asked me the following question saying that he was put in a situation when asked as to what is the reason for there being two sajdahs in each rak'at of namaaz?

Q: If I am in Salaah behind an Imaam and my wudhu breaks, do I complete the Salaah and repeat after or do I walk away at the point where my Salaah broke?

Q:

1. Is there any Hadith which mentions four sunnah before ishaa, the nawafil after zuhr and ishaa and also the two nafil after the witr.
2. Before jumua' are the four sunnats muakadah?  And after Jumma the six sunnats should one read four first or two first? I read in a book that Allamah Anwar ​Sha Kashmiri's view was two then four. What is the daleel for two nafil after Jumua'?
3. Is it sunnah to read Ayatul Kursi after every Salaah?

Q: Should one repeat the words of iqamat also and what is the virtue of repeating the words of the Azaan and iqaamat?

Q: If the imam is beardless, will the people be sinful if they remain quiet?

Q: At the ground where one places his feets during qiyaam, there is less than a dirham najasah and one notices this after salaah? Is the prayer valid?

Q: 

1. Is it permissible to perform Esha salah according to 12 degrees as mentioned in Ahsanul Fatawa and is the salah performed valid?
2. Is it permissible to perform Fajar salah according to 12 or 15 degrees and is the salah performed valid?

Q: Once I was Imam of Esha prayer, my wudhu broke after the second rakat. I did not know what to do, so I completed the namaz. Now what do I do? There were 11 people behind me.

Q: I wanted to ask on behalf of my mum. She reads namaaz and she reads while seated on a chair. She had a back operation and she can't bend down and her back has metal plates put in. Is it allowed that she does namaaz while seated on a chair with the musallah on the floor and performing namaaz with actions?