What is the ruling on doubting whether one or two prostrations were performed?
Praise be to Allah, and peace and blessings be upon our Master, the Messenger of Allah.
If a worshiper is in doubt regarding the number of units (rak'ahs) or prostrations (sajdahs) performed, he must build upon the minimum (i.e., assume the lower number) and perform the prostration of forgetfulness (Sujud al-Sahw) before the Salam at the end of the prayer. This is based on the report from ‘Ata’ ibn Yasar that the Messenger of Allah ﷺ said: 'When anyone of you is in doubt about his Salat (prayer) and does not know how many he has prayed, three or four (Rak'at) he should cast aside his doubt and base his prayer on what he is sure of. Then, he should perform two prostrations before Taslim (salutation). If he has prayed five Rak'at, they will make his Salat (prayer) an even number for him and if he has prayed exactly four, they (i.e. two prostrations) will be humiliation for the devil..' (Narrated by Abu Dawud).
It is stated in Al-Muqaddimah al-Hadramiyyah: 'If one doubts [whether he performed] a bowing (ruku’), a prostration, or a rak'ah, he must perform it and prostrate [for forgetfulness], even if the doubt is removed before the Salam—unless the doubt is removed before he performs what would potentially be an addition. Thus, if he doubts whether he prayed three or four, he is obligated to build upon the minimum.' And Allah the Exalted knows best.
Is it permissible for a woman to wear underwear while performing Umrah?
Yes, it is permissible for a woman to wear underwear while performing Umrah. This is because she should keep her regular clothes that cover all her body while being in a state of Ihram (ritual consecration) for Hajj, or Umrah. However, she should uncover her face and hands, but it is permissible for her to let her head-covering garment drape from her head down over her face when non-Mahram (i.e., marriageable) men pass by her. And Allah Knows Best.
What is the ruling on objecting to the Mosque Imam regarding the joining of prayers due to rain?
Praise be to Allah, and peace and blessings be upon our Master, the Messenger of Allah.
It is not permissible for any of the congregants to object to the Imam in the mosque, whether the objection is to demand the joining of prayers or to oppose it; for the general principle is that the Imam possesses the religious knowledge (Al-Ilm al-Shar‘i) that qualifies him to make the decision in this matter. And Allah the Exalted knows best."
Is it enough to say Tasbeeh (Saying Subhaana Rabbiya Al-‘Atheem during Rukoo`, and saying Subhaana Rabbiya Al-A‘laa during Sujood ) once, or twice during Rukoo`(Bowing in prayer) and Sujood (Prostration)?
All perfect praise be to Allah, The Lord of The Worlds Yes, saying Tasbeeh once during Rukoo` and Sujood is enough, provided that the worshiper`s attentiveness of the heart isn`t undermined during each. As regards the recompense, it depends on the number of Tasbeeh. And Allah Knows Best.