Can i connect me Imac to my TV {plasma} by cable so i can display my Computer screen on my tv? If so what cable do i need please ?
It depends on what inputs your plasma TV has. The short answer is yes if you have the correct cables. Your iMac has a mini DVI output, so at the minimum you would need a mini DVI to DVI adapter.
If your plasma has a VGA input and\or a HDMI input, you could use either one but both require an adapter. For example: If you were to use the HDMI input on the plasma - you would need the adapter I mentioned above plus a DVI to HDMI adapter. That would attach to a HDMI cable which would input to the plasma.
Additionally, you need a standard audio output cable from your iMac to the audio input on the plasma.
Regards.