[Bored chemist]

Now if all the heat had been absorbed by the air, you would have raised your 27.7 kg of air by about 50K

And mighty glad I was too- it started at -30 C.

That temperature rise would create an increase in pressure of roughly 1/5 of an atmosphere and exerting a force of over two tons on the window or door.
So now you know why I said "

Buildings leak; they have to or atmospheric pressure variations would make them unworkable.

BTW, why did you think I mentioned the fireplace?

[alancalverd]

Must be a different room.

The first one had a starting temperature of 283K and we were told to ignore the volume of the fireplace so it was reasonable to assume that the chimney was blocked.

0.18 atmospheres is about the pressure of a 100 mph wind on a bluff body. The internal doors might object but your front door and any modern double-glazed windows won't be too fussed. Come to think of it, most internal doors open into the room so it wouldn't even blow open.

Not that it's a problem as you would have switched off the heater and/or opened the window after about 200 seconds to avoid death.

Moral: wear a woolly sweater or a fur coat in cold weather. It works for every other mammal and people who work outdoors.

[hamdani yusuf (OP)]

No. It leaves the room and raises the atmosphere by a tiny amount, doing work against gravity.

OK. I think the results depend on which factors can be safely ignore, and which factors can't.
Assuming that the air is an ideal gas, its energy = pressure x volume = n. R. T
As long as the pressure and volume is constant, the energy is constant.
But the air temperature has increased, thus the number of air molecules must have decreased to make the equation balanced.
How far can the temperature increase without changing volume of the room?

[Bored chemist]

Must be a different room.

The first one had a starting temperature of 283K and we were told to ignore the volume of the fireplace so it was reasonable to assume that the chimney was blocked.

0.18 atmospheres is about the pressure of a 100 mph wind on a bluff body. The internal doors might object but your front door and any modern double-glazed windows won't be too fussed. Come to think of it, most internal doors open into the room so it wouldn't even blow open.

Not that it's a problem as you would have switched off the heater and/or opened the window after about 200 seconds to avoid death.

Moral: wear a woolly sweater or a fur coat in cold weather. It works for every other mammal and people who work outdoors.

I told you there was a fireplace (and, therefore a hole, called a chimney).
You assumed this was grounds to think the room was sealed.

That's on you.

In reality, a 5 degree temperature change would raise the air pressure in a sealed room to such an extent that it would make it hard to open the door.
People who require oxygen do not seal their houses.
Stop pretending that you were "right".
The answer is that there's no more energy in the room.

How far can the temperature increase without changing volume of the room?

Bricks expand by about 6 parts per million per degree C.
So the volume change is about 18 ppm/C

How much Alan's room would expand by under a pressure of something like 2 tons per square metre is anyone's guess.

[hamdani yusuf (OP)]

We can say that the energy change in the air inside the room is almost zero. But it's better if we specify the assumptions involved explicitly. To use the equation, the air must have characteristics of ideal gas. And the air composition hasn't changed due to the heating, which can be caused by evaporation of volatile substances in the room.

[alancalverd]

How much Alan's room would expand by under a pressure of something like 2 tons per square metre is anyone's guess.

Not a lot. It's pretty close to the pressure difference between an airliner cabin and the ambient at 30,000 ft, and those structures rarely fall apart.

[hamdani yusuf (OP)]

According to some physicists, this radiative cooling is not part of thermodynamics.

https://youtube.com/shorts/WerKkrkuwHg?feature=shared
The way they cook the hot dog is not covered by thermodynamics either.

[alancalverd]

Oh yes it is.

The current flow through the resistive hot dog generates heat which disperses through conduction, convection and radiation. At the primary contact points it gets hot enough (due to high local current density) to evaporate the sausage and generate a plasma which radiates all sorts of e.m. including visible light and possibly some ultraviolet.

[alancalverd]

People who require oxygen do not seal their houses.

We all live in a yellow submarine....

chorus:

...and we keep the windows open....

[hamdani yusuf (OP)]

Oh yes it is.

The current flow through the resistive hot dog generates heat which disperses through conduction, convection and radiation. At the primary contact points it gets hot enough (due to high local current density) to evaporate the sausage and generate a plasma which radiates all sorts of e.m. including visible light and possibly some ultraviolet.

Which thermodynamics formula you used?
Where does the heat come from and go to?

[Bored chemist]

How much Alan's room would expand by under a pressure of something like 2 tons per square metre is anyone's guess.

Not a lot. It's pretty close to the pressure difference between an airliner cabin and the ambient at 30,000 ft, and those structures rarely fall apart.

Have you seen how they build the doors on airliners?
Even in spite if that, when they do fail, it's not good news.

https://www.bbc.co.uk/news/business-67930977

You are in a hole Alan. Stop digging.

[Bored chemist]

People who require oxygen do not seal their houses.

We all live in a yellow submarine....

chorus:

...and we keep the windows open....

Really?
Where?
[Verse 1: Ringo Starr]
In the town where I was born
Lived a man who sailed to sea
And he told us of his life
In the land of submarines

[Verse 2: Ringo Starr]
So we sailed on to the sun
Till we found the sea of green
And we lived beneath the waves
In our yellow submarine

[Chorus: Ringo Starr, Paul McCartney, John Lennon & George Harrison]
We all live in a yellow submarine
Yellow submarine, yellow submarine
We all live in a yellow submarine
Yellow submarine, yellow submarine

[Verse 3: Ringo Starr]
And our friends are all aboard
Many more of them live next door
And the band begins to play

[Chorus: Ringo Starr, Paul McCartney, John Lennon & George Harrison]
We all live in a yellow submarine
Yellow submarine, yellow submarine
We all live in a yellow submarine
Yellow submarine, yellow submarine



[Bridge: Paul McCartney & John Lennon]
Full speed ahead, Mister Boatswain, full speed ahead
Full speed ahead it is, Sergeant
Cut the cable! Drop the cable!
Aye-aye, sir, aye-aye
Captain! Captain!

[Verse 4: Ringo Starr & John Lennon]
As we live a life of ease
Every one of us (Every one of us) has all we need (Has all we need)
Sky of blue (Sky of blue) and sea of green (Sea of green)
In our yellow (In our yellow) submarine (Submarine, ha-ha!)

[Chorus: Ringo Starr, Paul McCartney, John Lennon & George Harrison]
We all live in a yellow submarine
Yellow submarine, yellow submarine
We all live in a yellow submarine
Yellow submarine, yellow submarine
We all live in a yellow submarine
Yellow submarine, yellow submarine
We all live in a yellow submarine
Yellow submarine, yellow submarine

[alancalverd]

Sky of blue (Sky of blue) and sea of green

How do you know if you haven't got windows?

[hamdani yusuf (OP)]

According to some physicists, this radiative cooling is not part of thermodynamics.

https://youtube.com/shorts/WerKkrkuwHg?feature=shared
The way they cook the hot dog is not covered by thermodynamics either.

Magnifying The World's Brightest Flashlight (200,000 Lumens)

This video can give some reality checks for our current understanding of temperature.

In this case, the flashlight is cooler than the burning paper. Yet the energy flows from the flashlight to the paper.

[alancalverd]

No. The color temperature of the photons is about 4000 K.

[Bored chemist]

Sky of blue (Sky of blue) and sea of green

How do you know if you haven't got windows?

Periscope.
Or just a good memory.

Do you realise the point of windows is that you can see through them even if they are closed?

[Bored chemist]

According to some physicists, this radiative cooling is not part of thermodynamics.

https://youtube.com/shorts/WerKkrkuwHg?feature=shared
The way they cook the hot dog is not covered by thermodynamics either.

Magnifying The World's Brightest Flashlight (200,000 Lumens)

This video can give some reality checks for our current understanding of temperature.

In this case, the flashlight is cooler than the burning paper. Yet the energy flows from the flashlight to the paper.

It's not an equilibrium system. It doesn't really have a well defined  temperature.
It's not an equilibrium system. It doesn't really have a well defined  temperature.
It's not an equilibrium system. It doesn't really have a well defined  temperature.
It's not an equilibrium system. It doesn't really have a well defined  temperature.



I said it a few more times in the hope that  you will read it and remember what it means.

[alancalverd]

Now you really have confused the poor dear! Let me anticipate HY's response:

Thermodynamics is all about heat flow, and you don't get flow in an equilibrium system....

[hamdani yusuf (OP)]

It's not an equilibrium system. It doesn't really have a well defined  temperature.

Some physicists think that these cases are not covered by thermodynamics. Some others disagree.
I'd like to know the arguments from each sides.

No. The color temperature of the photons is about 4000 K.

The body of LED as well as the lens have definitive melting points. While they are functioning, we can safely say that their temperatures are below these points.

[hamdani yusuf (OP)]

Thermodynamics is all about heat flow, and you don't get flow in an equilibrium system....

Adiabatic processes are part of thermodynamics.

Thermodynamics is a branch of physics that deals with heat, work, and temperature, and their relation to energy, entropy, and the physical properties of matter and radiation. The behavior of these quantities is governed by the four laws of thermodynamics, which convey a quantitative description using measurable macroscopic physical quantities, but may be explained in terms of microscopic constituents by statistical mechanics. Thermodynamics applies to a wide variety of topics in science and engineering, especially physical chemistry, biochemistry, chemical engineering and mechanical engineering, but also in other complex fields such as meteorology.
https://en.m.wikipedia.org/wiki/Thermodynamics