The second tone in Mandarin Chinese is a rising tone, similar to the tone that we put at the end of a question in English… E.G Right? Really? Never?
The best way to learn this is through hearing it and hearing it described, the video and audio below do this:
As with all tones in Chinese, while the tone does directly affect the meaning of individual words, the tone that any particular word has in modern Chinese is merely a coincidence of the evolution of the language and has no particular significance.