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Sound and light

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GreatBigBadger
1238136.  Fri May 26, 2017 4:48 pm Reply with quote

Series N Episode 3, Sandi said that are ears responded to a wider frequency range than our eyes. The frequency range of sounds our ears can hear is roughly 20Hz - 20kHz, or 20kHz give or take. The range of light frequencies we can detect is 430-770THz or 340 terahertz. Our eyes therefore respond to roughly 17 million times the frequency range of our ears. Unless I've missed something?

 
Jenny
1238201.  Sat May 27, 2017 1:50 pm Reply with quote

Ooh interesting nitpick! Welcome to the forums. I don't have a clue about the issue you mention but there is bound to be somebody on these forums who does....

 
Leith
1238213.  Sat May 27, 2017 2:50 pm Reply with quote

Welcome GBB!
Interesting quibble. Clearly it's correct in absolute terms.

I think the apparent anomaly may be down to the interesting characteristics of frequency bands being measured on a logarithmic scale.
So the human hearing range spans two orders of magnitude, while the top end of the human visual response is less than double the frequency of the low end.

I expect there'll be a proper physicist and/or elf along in due course who can confirm or refute.

 
Leith
1238214.  Sat May 27, 2017 3:11 pm Reply with quote

(Not to suggest that you are or aren't a proper physicist, by the way, just that I'm not)

 
GreatBigBadger
1238216.  Sat May 27, 2017 5:20 pm Reply with quote

Ha, no I'm not a proper physicist, Leith, just a jobbing tech writer. I take your point about logarithmic scales - interesting wiggle.

 
Confucius
1250283.  Sat Sep 23, 2017 6:55 am Reply with quote

Leith wrote:
Welcome GBB!
Interesting quibble. Clearly it's correct in absolute terms.

I think the apparent anomaly may be down to the interesting characteristics of frequency bands being measured on a logarithmic scale.
So the human hearing range spans two orders of magnitude, while the top end of the human visual response is less than double the frequency of the low end.

I expect there'll be a proper physicist and/or elf along in due course who can confirm or refute.


That's pretty much how I see it. Pardon the pun.

Hearing 20Hz to 20,000Hz is 3 orders of magnitude (10^3) from 'top to bottom'.

Vision is within the same order of magnitude, ~430-770THz

Or perhaps it's just the 'journalistic' use of the phrase frequency range? If they expressed it as wavelength then obviously that of the visible spectrum is very narrow.

 

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