What happens to light (and sound)?

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G-CPTN
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What happens to light (and sound)?

#1 Post by G-CPTN » Sat Mar 11, 2023 4:41 am

Every night I visit the bathroom (several times).

I switch on the light (which 'floods' the bathroom), then switch it off.

Where does it go to?

Does it escape through the adjoining room?

Does it join up with dark matter (that we are lead to believe exists in abundance around us)?

I think we should be told.

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Re: What happens to light (and sound)?

#2 Post by llondel » Sat Mar 11, 2023 4:43 am

It all gets absorbed into the surrounding walls, and ultimately ends up as heat. Every time you switch on the light, you are hastening the heat death of the universe.

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Re: What happens to light (and sound)?

#3 Post by G-CPTN » Sat Mar 11, 2023 4:47 am

That seems plausible, as I have just had to open the bedroom window as I was 'overheating'.

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Re: What happens to light (and sound)?

#4 Post by PHXPhlyer » Sat Mar 11, 2023 3:08 pm

Cover the walls, floor, and ceiling with mirrors.
That should hold the light in until you open the door.

PP

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Re: What happens to light (and sound)?

#5 Post by Boac » Sat Mar 11, 2023 3:35 pm

On reflection, that should work.

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Re: What happens to light (and sound)?

#6 Post by G~Man » Sat Mar 11, 2023 5:58 pm

Put a flashlight in the room with the back cover off----that will capture it and you can use it later as needed. You just need batteries to stop the unit from imploding while holding all that energy. They work great--I have several.
B-) Life may not be the party you hoped for, but while you're here, you may as well dance. B-)

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Re: What happens to light (and sound)?

#7 Post by Fox3WheresMyBanana » Sat Mar 11, 2023 6:28 pm

..and remember to switch the flashlight on before picking it up.
That way, it's lighter, as there are more lift bernoullis around.

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Re: What happens to light (and sound)?

#8 Post by bob2s » Sat Mar 11, 2023 10:36 pm

.and remember to switch the flashlight on before picking it up.
That would not work as I believe that flashlights are only used for carrying around dead batteries, hence no light when switched on.

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Re: What happens to light (and sound)?

#9 Post by Fox3WheresMyBanana » Sat Mar 11, 2023 11:12 pm

Good point, well made.
As ever with scientists, I provided information which was theoretically correct but of no practical use.

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Re: What happens to light (and sound)?

#10 Post by OneHungLow » Fri Apr 14, 2023 2:39 pm

llondel wrote:
Sat Mar 11, 2023 4:43 am
It all gets absorbed into the surrounding walls, and ultimately ends up as heat. Every time you switch on the light, you are hastening the heat death of the universe.
Ah one of Kirchhoff's perfect black bodies!

A Vantablack moment...



Seems I am behind the times...



Probably still not as black as Adrian Mole's Noddy wallpaper after he painted it black, and still failed to hide Noddy's ubiquitous face. :)
The observer of fools in military south and north...

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Re: What happens to light (and sound)?

#11 Post by OneHungLow » Sat Apr 15, 2023 1:13 pm

I thoroughly enjoyed this potted history of the science of light. I share it here.


The observer of fools in military south and north...

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Re: What happens to light (and sound)?

#12 Post by OFSO » Wed Nov 08, 2023 5:27 pm

Since Mrs OFSO and her new Knee moved into the guest bedroom (she's now back with me) and the new LED street lights are not bright enough to illuminate the way to the WC, I bought two more solar lights, but portable, which I charge up on the terrace all day but bring into the passage at night. In answer to the OP, therefore, a miniscule number of the sun's photons are captured and stored each day and released overnight indoors. Some disappear down the WC but the majority bounce off the light walls and fall onto the carpet, which is dark, raising the temperature.

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Re: What happens to light (and sound)?

#13 Post by OFSO » Fri Nov 10, 2023 7:09 pm

Further question: one can reflect light many times between two or more mirrors. Is there a limit to this ?

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Re: What happens to light (and sound)?

#14 Post by Boac » Fri Nov 10, 2023 7:24 pm

On reflection (sorry...) there has to be, since energy will be lost at each reflection as the light passes through the surface of the mirror.

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Re: What happens to light (and sound)?

#15 Post by tango15 » Fri Nov 10, 2023 7:26 pm

I'm completely in the dark with this...

What you need is a neighbour opposite who has a powerful light on the path which illuminates every time one of their five cats goes for a stroll. The light then reflects through the frosted glass in the bathroom sufficiently for one to be able to aim as accurately as possible, and since I live alone, I don't have to worry about leaving the seat up! :))

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Re: What happens to light (and sound)?

#16 Post by jimtherev » Sat Nov 11, 2023 12:03 am

tango15 wrote:
Fri Nov 10, 2023 7:26 pm
I'm completely in the dark with this...

What you need is a neighbour opposite who has a powerful light on the path which illuminates every time one of their five cats goes for a stroll. The light then reflects through the frosted glass in the bathroom sufficiently for one to be able to aim as accurately as possible, and since I live alone, I don't have to worry about leaving the seat up! :))
I don't have an obliging neighbour; instead #1 son and I have a tradition of exchanging wacky and usually useless Christmas presents. However, the 2021 present met with approval, and we're still pleased by the welcoming light in the bathroom whenever it's approached.

Light.jpg
Light.jpg (23.67 KiB) Viewed 5058 times

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Re: What happens to light (and sound)?

#17 Post by Fox3WheresMyBanana » Sat Nov 11, 2023 12:13 am

since energy will be lost at each reflection as the light passes through the surface of the mirror.
This is the reason astronomical mirrors are put on the front face of the glass, not the back.

It does make cleaning a specialist operation.

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Re: What happens to light (and sound)?

#18 Post by Boac » Sat Nov 11, 2023 8:40 am

jtr wrote:the welcoming light in the bathroom whenever it's approached.
As it is 'motion-activated, Jim, do you need a torch if you just go for a pee? =))

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Re: What happens to light (and sound)?

#19 Post by G-CPTN » Sat Nov 11, 2023 9:19 am

Just wave it from side to side.

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