Re: Want to prove E=mc²? University labs should try this!

Prokaryotic, I was thinking about what you wrote on the cavity behaving
as a black body and, as I wrote before, I completely disagree to take it
as a black body radiating energy, once equilibrium has been reached.
My main doubt was that, once in equilibrium and having gained as heat
all the energy supplied by the 5W laser, the aluminum cavity HAD TO
radiate using the external surface AS WELL AS the internal surface. I
thought that almost HALF of the heat was going to be radiated INTO THE
CAVITY.
Injecting 5 Joules/sec makes the cavity (initially at room temperature
of 300K) to reach thermal equilibrium in a couple of minutes.
I used ChatGPT, which calculated the thermal equilibrium at 707 K, which
is reached in 191 seconds.
This means that half of the accumulated 955 Joules remain within the
cavity. The extra mass added to the 2 grams cavity would be 5.306E-12
grams, adding an extra weight of 0.052 nanoNewtons.
Even if this is a very low weight (or mass), it's almost 10,000 times
higher than in previous (and wrong) calculations.
I believe that such weight can be measured by advanced technology and,
besides, it's a steady value, so measurements are not limited by time.
I can't transcribe the answers of ChatGPT (I failed once), so I write
here my questions so you or anybody can duplicate the chat.
...................
Q: I have one sphere made of aluminum (2 grams), with a tiny hole of 3
mm^2 used to inject a 5 watts (550 nm) green laser beam. The sphere has
a 5 cm radius and a thickness of 0.1 cm.. It has been calculated that
the 5 Joules per second are completely absorbed by the aluminum. Does
the sphere (a cavity) radiates the  absorbed 5 Joules per second into
the cavity, as well a part of it by its external surface? In what
proportions?
A: approximately 49% of the absorbed energy radiates into the cavity,
and 51% radiates externally.
..................
Q: What would be the temperature of the sphere?
A: The equilibrium temperature of the sphere is approximately 707 K (434
°C).
...................
Q: Exist a specific wavelength at which the heat is radiated?
A: Using Wien's Displacement Law, the peak energy is radiated  across a
broad spectrum, primarily in the infrared. Most radiation is in the
mid-infrared range (2 - 25 μm), with a peak at 4.1 μm.
................
Q: How many seconds would take to reach thermal equilibrium at 707 K?
A: The sphere would take approximately 191 seconds (about 3 minutes) to
reach thermal equilibrium at 707 K under the 5 W laser input.
..................
ChatGPT used formulae from Stefan, Wien, Planck and many others to
provide the results.