No current circulating British coin has a diameter of exactly 3 cm. The closest is the £2 coin with a diameter of 2.84 cm.
In the UK, the highest value coin in current wide circulation is the £2 coin.
A UK one pence coin has a diameter of 20.32 millimetres. A two pence coin has a diameter of 25.9mm. A five pence has a diameter of 18mm. A ten pence has a diameter of 24.5mm. A twenty pence is heptagonal and has a diameter of 21.4mm. A fifty pence is heptagonal and has a diameter of 27.3mm. A one pound coin has a diameter of 22.5mm. A two pound coin has a diameter of 28.4mm.
The British two pence coins issued from 1971 through 1992 are bronze, 25.91mm in diameter, and weigh 7.12 grams. Composition was changed in mid 1992 to copper-plated steel (although there do still seem to have been some bronze coins issued through 2000), which are 25.86mm in diameter and weigh 7.14 grams.
The Royal Mint did not produce any gold coins in 1971. The closest in appearance to a gold coin would be the 2 New Pence, 1 New Penny and Half New Penny coins which are all made from bronze and have the denomination of the coins inscribed on the reverse. The 2 New Penny coin is 25.91 mm in diameter and has the Welsh plumes on the reverse. The 1 New Penny coin is 20.32 mm in diameter and has a crowned portcullis on the reverse. The Half New Penny coin is 17.14 mm in diameter and has a crown on the reverse.
A decimal penny used in the UK, has a diameter of exactly 2 centimetres (20 millimetres). Therefore, use either cm or mm.
Sounds like an Indian coin - not UK?
It depends on the nation. The smallest circulating US coin is a dime, but for other countries it really depends. But the smallest historic coin that the US has minted for circulation is the silver three cent piece.
Such a coin does not exist. The Royal Mint produced no copper (or bronze) Twopence coins from 1798 until decimalisation in 1971. If such a coin did exist, it would be something in the order of 36 to 41 mm in diameter and very heavy (significantly larger and heavier than a Penny coin from the same period). If the coin is very badly tarnished, you may have a sterling silver Maundy Twopence which would be 13 mm in diameter. George V on the obverse and a crowned 2 on the reverse.
It was the 20pence coin
The UK does not have a president, current Prime Minister is David Cameron
Somewhere between £3.00 to £5.00 in the UK. With current exchange rates, you will have to work out the value yourself if you aren't in England. It depends on the condition of the coin, who wants to buy it. You may have to take it to an expert to inspect.
1982