As Salaam Alaykum Dear Sir,
I have question about Zakat and Khums.
Zakat: I understand zakat is wajib on gold and silver coins used as currency at time of Prophet Muhammad (PBUH) and his family.  The gold or silver coin were used as currency that allowed a person to buy things from grocery , horses ,homes, all other items that we buy in modern day paper currency. The currency may have devalued but it is serving still the same functions of buying things regarding of material of currency gold, silver or paper currency.  What is reason Shia school of thought goes by material but not the value it provides as to function of buying things of value like cars, grocery. Did Prophet Muhammad say something like Zakat not applicable of paper currency, or it is in kind only like gold and silver coins but not on buying capability. Are there clear hadeeths to this ?
Khums: I major known translation khums appears to be in context of war . I see 2 references in Quran for the word ghanimatum both in war context and chapter seems to speak about windfall. To some like me who has no background of Arabic looking at english translation seems it is talking about some sudden huge wealth like in context of war. Treasure seems on of them. Is there a hadeeth that clearly says that one needs to take out khums on salary /wages ? In that case how do we treat salary differently in case of Zakat and Khums ? If khums is wajib on salary than in days of the prophet the salary a person would get would be in dinar /dirhams (silver or gold coins) but today we get currency in paper money so the form has changed here. Is there a clear hadeeth from Prophet that khums needs to be given on wages earned ?
Second in gaibat Imam how do we come to conclusion that khums should be given to Alim in Imam\’s absence ? Is it there in khums verse where those who receive khums is mentioned ?
Please help me understand by providing clear hadeeths ?
https://www.al-islam.org/khums-islamic-tax-sayyid-muhammad-rizvi/khums-quran-history#meaning-%E2%80%9Cghanimtum%E2%80%9D
The hadeeth above does not appear to be crystal clear to me for some reason.
Was Salaam,
Zoher