How to tell the difference [επιλυμένο]

I have a 2011 10 cent coin but I am not sure what one it is - there are two links and one is
rarer than the other. How do you tell the difference (other than weight or other stuff like that)?

https://en.numista.com/catalogue/pieces3297.html

https://en.numista.com/catalogue/pieces130092.html

The answer is on those pages - the first one says the metal is copper-plated steel and
the second one says it is just copper - so a magnet will tell the difference.