That all depends on the resolution of the video. You can check the Sony site for your particular camera model or your owner's manual. Usually there is a breakdown of how many minutes can be recorded at various resolution in the owner's manual.
My Easyshare Z990 (it's a camera), in 1080p mode, goes for about 10 minutes with my 32G card; but, it even depends on the video and all the sound, too.