A:AnswerYes you are correct and I do the same thing myself.
If volume is still coming from your computer, go to your volume preferences and choose "External Speakers" which should also show some ID of the TV you are connected to.
A:AnswerYou would need these cables, if you wanted to hook up any accessories to your TV such as a gaming console, or a DVD/Blue Ray player. That is the sole purpose of cables such as these, has nothing to do with cable. If you don't plan on hooking anything up to your TV, these are not a necessity
A:AnswerYes, it handles, as do most if not all HDMI cables, handle both audio and video signals. I have mine connected from a 3D/4K Blu Ray Player to a 4K Smart TV paired with a Sony Sound Bar and Subwoofer; there are no problems with either the picture or sound.
A:AnswerThe cable is 3 feet. 3' is feet 3" is inches but I can understand at this price why you would ask. I bought several for my own home and they work great. 3 feet is plenty to connect from your tv to device.
Thank you very much for your interest in our 4K Ultra HD HDMI cable. I saw your question about the rating of this cable and wanted to let you know that this cable is not in-wall rated but it will perform amazing thanks to the 3-layer cable shielding that prevents interference.
I hope you enjoy this and other Dynex products.
Arely R. - Dynex Support