Is it permissible for a woman to go out wearing bright colors?
Bright colors are part of a woman`s adornment, and it is impermissible for her to show it to people other than her husband, or one of her Mahrams(Unmarriageable kin).
Is Iddah (waiting period) incumbent on an old lady whose husband had died?
Upon the death of the husband, Iddah is incumbent on the wife regardless of her age.
How long is the` Iddah(waiting period) of a divorced woman?
If a woman is pregnant at the time of divorce, then her 'Iddah (waiting period) expires when she gives birth to the baby. If she is in a state of menstruation, then her `Iddah expires when she finishes three menses. However, if she doesn`t have menses, then her `Iddah expires after three months.
My husband told me that he concluded our marriage with a fake name that belongs to another person, because he was sentenced. Nowadays, he brought an ID, passport and birth certificate with the his current name. What is the ruling on being married to him?
praise be to Allah, The Lord of The Worlds, and may His peace and blessings be upon our Prophet Muhammad and upon all of his family and companions.
As regards being married to the person mentioned in your question: The marriage is valid so long as he was the same person your guardian concluded the marriage with, even if he changed his name i.e. if your marriage contract was concluded with the same person, since what counts regarding marriage is the persons not names. And Allah Knows Best.