Hi,
the RCA-Jacks of an A2000 are for audio and monochrome-video.
If you want to have a colored picture you could either buy an A520 to connect to the antenna-input of the TV or -- if your TV is able to display RGB -- you could purchase a cable to connect your Amigas video-output (23-pin connector) to the AV-input (scart) of your TV. This would be the better choise, the picture is much better than with an A520.
Noster