Light released within a sphere with a perfectly opaque inner surface

In summary: An opaque surface just means that no light can pass through it. It does not guarantee that all light will be reflected or absorbed. So the inner area would not necessarily remain bright for a prolonged period of time or indefinitely.
  • #1
antwan89
2
0
I have a question that has been puzzling me. If a beam of light was released within a sphere or cube with a completely opaque inner surface would the inner area remain bright for a prolonged period of time or perhaps indefinitely assuming a vacuum exists within the sphere?

Perhaps a perfectly opaque surface does not exist? Perhaps a mirror made from a superconductor would be a more effective inner surface assuming the mirror isn't already the most opaque surface available, although I understand there heat losses occur when light is reflected off a mirrored surface.
 
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  • #2
Opaque (=not transparent) is not enough, a black sheet of paper is opaque as well. If the surface is a perfect mirror, then sure, the light would stay in.

Superconductors are extremely close to perfect mirrors - with microwaves, you can "trap" light for ~100 milliseconds with them (source), and the radio-frequency cavities used for particle accelerators achieve similar Q-factors as well.
 
  • #3
than you mfb, but isn't opaque also defined as "Impenetrable by light; neither transparent nor translucent." A sheet of black paper is translucent is it not? To the human eye it will block out most of the light, but some will escape.

If a truly Opaque material was used, surely no light could escape the sphere and it would remain permanently bright?
 
  • #4
No. "No light could escape" if the light is absorbed by the surface. "Opaque" does NOT mean "perfectly reflective".
 
  • #5
antwan89 said:
A sheet of black paper is translucent is it not?
That's not the important point (add multiple layers if you like). A black surface does not reflect light, even if the material behind it does not allow any light to pass.

If a truly Opaque material was used, surely no light could escape the sphere and it would remain permanently bright?
The light can get absorbed.
 

1. What is "light released within a sphere with a perfectly opaque inner surface"?

Light released within a sphere with a perfectly opaque inner surface refers to the phenomenon of light being contained within a spherical object that has a completely non-reflective inner surface. This means that all light that enters the sphere is absorbed and does not escape.

2. How is the light released within a sphere with a perfectly opaque inner surface produced?

The light released within a sphere with a perfectly opaque inner surface is typically produced through the use of a light source, such as a bulb or LED, that emits light in all directions. The light enters the sphere and is absorbed by the inner surface, causing it to be contained within the spherical object.

3. What is the purpose of using a perfectly opaque inner surface in a sphere?

The purpose of using a perfectly opaque inner surface in a sphere is to create a controlled environment for the light. By absorbing all of the light that enters the sphere, the inner surface ensures that the light remains contained and does not escape, allowing for precise measurements and experiments to be conducted.

4. How does the light behave within a sphere with a perfectly opaque inner surface?

The light within a sphere with a perfectly opaque inner surface behaves in a similar manner to light in a closed container. The light bounces around inside the sphere, continually being absorbed and re-emitted by the inner surface. This creates a uniform distribution of light within the sphere.

5. What are some real-world applications for light released within a sphere with a perfectly opaque inner surface?

Light released within a sphere with a perfectly opaque inner surface has various applications in fields such as optics, astronomy, and physics. It can be used to study the behavior of light in a controlled environment, measure the properties of different materials, and even simulate the conditions of outer space. It is also commonly used in experiments and demonstrations to showcase the properties of light and its interactions with matter.

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