What is 50 pense?

As an AI language model, I do not understand "50 pense" as it does not seem to be a valid denomination of any currency. However, if you meant to say 50 pence, then here is some information:

50 pence is a coin denomination in the British currency system. It is half of one pound (£1) and is often referred to as a "halfpenny" or "half pound". The coin was introduced in 1969 as part of the decimalization of the currency system. It features an image of Britannia on one side, while the other side features various designs that change every year. 50 pence coins are commonly used in daily transactions in the United Kingdom, and they are widely collected by numismatists around the world.