Comparision of sound and light

Usually light travels faster than sound.However, when we switch a television set on,the picture comes later sound.What is the reason behind this : ?


  • Abhishek Rawal
    Abhishek Rawal
    In Television (considering it to be CRT TV) Cathode ray tube takes some time to properly heat, and once it is properly heated,it displays image on fluorescent screen.

    Bit Off-topic :
    You know,i had one TV which I was using for studies, it had one problem i.e Sound was obtained from the moment it is started but image appears after 2-3 hours, because CRT was taking very long in heating.
  • lal
    It is totally a different scenario. Sound and picture, are both transmitted as a electromagnetic wave from the transmitting station. Later, It is the television circuit which synthesises sound and picture in a TV. It depeneds on the circuit on which output comes first but not on the propagation speed of sound or light.

    Say you are watching a TV from quite a distance and the sound is pumped up enough to reach you. If the screen and speakers are both at same distance from you, you'll notice the conversations/voice lag!
  • rahul69
    Usually light travels faster than sound.However, when we switch a television set on,the picture comes later sound.What is the reason behind this : ?
    We see lightning flash during lightning, before we hear thunder, and nature doesn't lie 😉
  • Jeffrey Arulraj
    Jeffrey Arulraj
    Mate the relative time difference is really less

    Sound takes 0.00303 s to travel a metre
    At the same time light takes nearly a nano second to travel the same time

    That can cause lag between both.

    But in TV you don't notice lag as the video is also a sequence of images played rapidly for a few milli second. And this turn on and off time allows both the sound and light to sync with each other splendidly

    The 25 frames per second allows us to watch and listen at the same time
  • Ahsanul haque
    Ahsanul haque
    The speed of light is 299,792,458 meters-per-second, which
    is approximately 186,000 miles per second. This speed is usually same, no
    matter about temperature or medium effect is travelling through it. But Sounds
    speed is 32 miles per second. Lightning is a massive electrostatic discharge
    between the electrically charged regions within clouds or between a cloud and
    the Earth's surface. In Lighting Thunder Light we noticed it first after then
    sound. After few mechanism then TV lights on.

You are reading an archived discussion.

Related Posts

The title itself explains everything, I look forward to responses from every Cean on How they study a certain subject? I mean cram or some special procedure they follow that...
I have Quickheal installed on my PC. This has expired. Now I want to renew it. The cost of it is INR 2600 for 3 years while Bitdefender costs INR...
I'm interested in knowing the reasons why Safari, Chrome and Firefox have different memory utilisation and battery consumption rates. Each of these browsers uses a different rendering engine (Google's Chrome...
Just spotted this new super car from Nissan and it looks to have arrived from future. Check Nissan BladeGlider on display at the Tokyo Motor Show -
Following the leads by Airtel & Reliance Jio, Aircel could be the next mobile network operator in India to launch 4G services. The operator is currently testing the network in...