What is 'k' in 1k or 500k?

In general people used to represent the value of thosands in term of 'k' Hence 1k=1000 ans similarly fro each number with k at last represent 1000 times that no. I feel you had not read phsics so you had confusion in it. We use prefix and suffix like kg where k is kilo with g gram similar in km is kilo with m meter and so on with other metric. I can tell you what those are as K - 1000 In similar we millions can be written is m or mn or billions as b or bn

it depends in monetary terms 1K means 1,000 eg $1,000 so 500k would be $500,000. If you mean in terms of computers then your wrong no computer data would be 1k or 100K etc. Computer data is measured either in KB or MB not just K on its own. I think what you are thinking of is monetary terms.

k is 1000, so 50k means 50000

There is a lot of meaning on k. Like it could mean kilometers or maybe a thousand or even kilobyte. it will really depend on how it will be used and the context of the sentence.

K is a short form for 1,000. Any number before a K means that number x 1000.

k refers to "thousand" in monetary terms . It is kind of an abreviation when writing money in thousands. For example, 1k would refer to one thousand...