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.
Is it permissible to listen to chants praising the Prophet if accompanied by musical instruments?
If singing, or chanting in praise of the Prophet was accompanied by a forbidden musical instrument, then it is forbidden.
A woman committed adultery with several men and gave birth to a baby. Who is the father?
All perfect praise be to Allah the Lord of the Worlds. May His peace and blessings be upon our Prophet Mohammad and upon all his family and companions.
The adulterers must be punished as prescribed in Sharia for they have incurred the wrath of Almighty Allah. Therefore, they must hasten to make repentance and ask Allah for forgiveness. However, the child born out of this unlawful relation is attributed to the mother. And Allah The Almighty Knows Best.
Is it permissible for a wife to leave her house without asking her husband?
It is impermissible for the wife to leave her house without asking her husband except for a sound reason.