How do I know if my  TV is a 120 hz TV?

I'm wondering this because I have a 4K TV and I'm planning on getting an Xbox One Series X.

?2020-11-09T05:22:40Z

Read the manual to find the specifications list.

Anonymous2020-11-08T23:08:15Z

4K TVs are generally not 120Hz. If you named a brand and model number its specifications could be looked up.
Higher resolution in gaming gets lower fps. Prepare for that.