what is ex-dividend date and what is dividend date?

Answer 1

Ex-dividend is used to identify the owner of a stock on that date. The dividend date is when the dividend is actually issued.

Answer 2

The ex-dividend date is the date you must own the stock to receive the dividend. The dividend date is the date the dividend is actually paid. The difference between the two dates results from the fact that stock sales are actually settled after the date of the sale. (I believe it is 3 days, but don't trust me on that.)