Explanation:

The RBI was established in 1935 and was nationalised in 1949. While prior to 1949, all currency notes were issued on behalf of the Ministry of Finance, post RBI's nationalisation, the apex bank was delegated the responsibility of issuing the currency.

While all denominations of currency notes are signed by the RBI Governor, only as a matter of convention the one rupee note continued to be signed by the Finance Secretary.The one rupee note however went out of circulation after 1994 and was treated as token currency note.