Why is a lion shown on an Indian currency note?

Answer 1

If you look at the Ashoka pillar at Sarnath (or a picture of it) you will find the capital of the pillar has 4 lions sitting back to back. The lion represents the attainment of Buddha-hood. The four lions surmounting the capital symbolize the kingship of the Buddha and his roar over the four directions. The four lions (one hidden from view) represent Power, Courage, Pride and Confidence.

There is also a non-religious interpretation to the symbol, describing the four lions as the symbol of Ashoka rule in four directions.

Just like Buddha, his follower Ashoka wanted to spread the message of peace and friendship. Similarly India after she gained independence wanted to spread the same message. So India adopted the emblem of 4 lions after she gained independence. That is why the emblem is used on indian currencies.