how do I show power point & Word presentations with sound on a smart TV ??
Do I need a cable from lap top to TV ??
It depends on your laptop. If it can share the screen wirelessly (through Screen Mirror), the audio will connect wirelessly as well. Screen Mirror shows up as another input option, like HDMI. I have a Windows 10 laptop that I bought last year and it works well on this TV.
You should also be able to connect your laptop with an HDMI cable, which transmits both sound and video. Just be sure to select the right HDMI source on your TV. Your laptop should send both audio and video automatically once connected.