GST QUERY..,

No ... the common credit means that part of input tax credit which cannot be identified specifically to taxable supply or Exempted Supply or non-business purpose, rather commonly used for taxable, Exempted and for Non-business supplies.
But in your case you are not having Taxable Supplies.
Perfect example of Common Credit is mobile phone bill of Proprietor , which used in both personal calls & business calls.
2. When capital goods used for making both. taxable & non taxable/Exempted supplies Rule 43 is applicable.

Note : As you are not having any taxable supplies. so you must reverse the whole ITC on capital goods in same month , because if you go by rule 43 (monthly reversal) , the interest is applicable in term of Rule 43(1)(h) need to be paid.

"you go by rule 43 (monthly reversal) , the interest is applicable in term of Rule 43(1)(h) need to be paid." sir interest is applicable every time? when this interest is applicable it is only for delay in Reversing input i monthy or not?

YES ..... INTEREST APPLICABLE EVERY REVERSAL. SO ADVISABLE DO NOT CLAIM ITC FOR THE SAME & BOOK THE WHOLE AMOUNT INCLUDING GST TO CAPITAL GOODS

1.That means it is compulsory to pay interest  in monthly along with monthly proprotionate itc reversal as per rule 43 no relaxation for this interest  , am i right?
2. Sir, so that it is better to not to claim gst common input on capital goods? Because this interest for 60 month, it is a big cost, am i right?
3.Sir in case delay in Reversing monthly itc eg:- 3 months itc reversal as per rule 43 is reversed in the one month, then is any further interest is applicable for such reversal delay in addittion to above interest?
4. If yes what is te rate of interest?

Normaly 18%pa and you can claim inelegible itc Interest Rate is 24%pa