Why Does a Black Object Reflect Light Despite Absorbing All Colours?

  • Context: High School 
  • Thread starter Thread starter no idea
  • Start date Start date
  • Tags Tags
    Light
Click For Summary

Discussion Overview

The discussion revolves around the phenomenon of light reflection and absorption in black objects, exploring why a black object reflects some light despite absorbing all colors. Participants delve into theoretical explanations and concepts related to color perception, light behavior, and the properties of materials.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • One participant questions why a black object, which absorbs all colors, still reflects some light when observed.
  • Another participant proposes two potential explanations: one involving changes in the electronic configuration of molecules affecting light absorption and reflection, and the other referencing the law of black bodies and the re-emission of light energy depending on temperature.
  • A different participant notes that a truly black object would be invisible, emphasizing that all observed black objects reflect some light.
  • This participant also clarifies that an object's color is determined by what it absorbs and reflects, contrasting black objects with red objects and mirrors.
  • Another participant introduces the concept of Brewster's angle, suggesting it relates to total reflection of light, although they admit to limited knowledge on the topic.

Areas of Agreement / Disagreement

Participants express various viewpoints on the mechanisms of light reflection and absorption, indicating that multiple competing explanations exist without a clear consensus on the primary reasons behind the observed phenomena.

Contextual Notes

Some explanations depend on specific assumptions about material properties and the conditions under which light interacts with surfaces. The discussion includes references to complex concepts like electronic configurations and the law of black bodies, which may not be fully resolved.

Who May Find This Useful

This discussion may be of interest to those exploring optics, material science, or the physics of light and color perception.

no idea
Messages
93
Reaction score
0
why the light reflected by a object is not the object's colour but it is sunlight?for example , a black object absorb all colour so we can see it is 'black' but why it still reflect some light when we watch it/
 
Science news on Phys.org
I'm not sure but here's what I think. There are two ways I can think of for the object to reflect some of the light: first, the light that is absorbed by object changes the electronic config. of the molecule's electrons and if at that same moment another wave of light hits the molecule rearranged, maybe that molecule won't have the same absorbant effect on light and may reflect it instead. Second, there is a the law of black bodies that say that depending on the temperature, an object reemits all or some of the light energie it receives, usually this light is not visible but it could be.

hope this satisfies you.. at least a little bit.
 
thx

thx very much
 
Also, if a black object were totally black, it would essentially be invisible. Every black object you've seen refelcts a little bit of light.

An object's color is determined (less technical than Mikado's good response) by what it absorbs and reflects. A red car is red because it absorbs everything except red. An object that reflects (but scatters) all colors is white - an object that reflects all colors at the angle of incidence is a mirror.
 
There is another effect, having to with Brewster angle, where light is totally reflected, irrespective of the surface material. I am not too well acquainted with it. Try google?
 

Similar threads

  • · Replies 10 ·
Replies
10
Views
2K
  • · Replies 81 ·
3
Replies
81
Views
9K
  • · Replies 3 ·
Replies
3
Views
5K
  • · Replies 5 ·
Replies
5
Views
2K
  • · Replies 4 ·
Replies
4
Views
3K
  • · Replies 11 ·
Replies
11
Views
2K
  • · Replies 5 ·
Replies
5
Views
3K
  • · Replies 8 ·
Replies
8
Views
10K
  • · Replies 6 ·
Replies
6
Views
3K
  • · Replies 1 ·
Replies
1
Views
2K