Laser Beams Deflected Off of Nothing but Air for First Time Ever in Breakthrough Patent Pending Process - The Debrief::An international team of scientists report that they have successfully used acoustics to deflect laser beams in an engineering first.

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70 points

I didn’t know the answer to this so I looked it up - yes. Over 120 Db can cause damage even if it’s ultrasonic and you can’t hear it. Apparently at 155Db the heat created by the sound wave can be dangerous as well.

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40 points
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Just a small note, it’s written dB, small “d”, big “B”.

“B” is the unit symbol for bel and “d” is the symbol for the SI prefix deci, a tenth.

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8 points

Oops, thanks for the correction!

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0 points

i love you

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1 point
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13 points

Trust this guy, when it comes to the small d he knows everything about it.

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1 point

In that case can we use just B. MB, etc.

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3 points

Oh yes, sure you can, 140 dB is 0.000014 MB. The confusing thing is just that the non-SI unit byte also uses the symbol “B” and uses the SI prefix “M” quite often.

Sometimes when I calculate optical power levels I actually use B in between. For example:

How much signal is 88 optical channels at 1.6 dBm of power each?

0 dBm = 1 mW by definition

1.6 dB = 0.16 B = log10 ( x ) --> x = 10 ^ 0.16 = 1.45

So 1.6 dBm is 1.45 * 1 mW = 1.45 mW

Then 88 channels is 88 * 1.45 mW = 127.60 mW = 127.60 * 1 mW

log10(127.60) = 2.11 B = 21.1 dB

So 127.20 mW is 21.1 dBm, just below the output specification of our amplifier, good, nothing should melt.

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