Physics in television

[physics246]

How does physics play a role in televisions with respect to light waves, radio waves, and sound waves. Also, if the speed of light is faster than the speed of sound, why does the picture and sound arrive at sync in a television. I just need to know a little bit about the basis of a television, not too much.

Thank you

[arildno]

If the sound as you hear it from the television had actually been transported in the shape of a sound wave from the sender, then a lot of eardums on the way would have exploded.

The information necessary to construct the sound inside your television set is carried by electro-magnetic waves just as the information necessary to construct the image on your television set.

That is, actual image and sound production happens within your television set, on basis of the information carried to it as a sequence of electric signals in the cable; that sequence again having been started at your antenna on receiving the incoming EM wave.

[mathman]

Also, if the speed of light is faster than the speed of sound, why does the picture and sound arrive at sync in a television.
Speed of sound is roughly 1000 ft/sec., so if you are 10 feet away from the screen, it arrives in about .01 sec - you can't tell the difference.

[physics246]

1. Is it possible to convert sound waves (longitudinal) into electromagnetic waves (transverse)
2. I know that the picture travels as an electromagnetic wave to get from the station to the T.V., but when it gets from your monitor to your eyes, how does it travel.

[arildno]

1. Yes. That coversion process is happening when the journalist speaks into his microphone. The sound waves hitting the microphone triggers the apparatus to deliver its signals onwards.

2. As waves in the spectrum of visible light.

[Edgardo]

Hello, you may find these links interesting:
How Radio Works (http://electronics.howstuffworks.com/radio.htm)
How television works (http://www.howstuffworks.com/tv.htm)
How telephones work (http://electronics.howstuffworks.com/telephone.htm)
How microphones work (http://electronics.howstuffworks.com/question309.htm)