# How will the force of Light change with absorbtion/reflection?

• AshleyTomo
In summary, the conversation discusses the relationship between the force of light and whether it is absorbed or reflected by an object. It is mentioned that for black materials, the light is absorbed and the change in momentum is equivalent to the momentum of the light photon. However, for white materials, the direction of the photons changes, resulting in a change in momentum of 2p. The concept of nonlinear optics is also mentioned as a factor that may change the index of refraction for high powered light.
AshleyTomo
I am confused about whether or not the force that light exerts on an object (let's say that the power it has is 1 Watt) changes whether is is absorbed or reflected.

I know that W = Fv, but is there more to it than that?

Thank you for the help!

conservation of momentum.

For black materials (assuming black is equivelent to absorbs all frequencies) the light is absorbed, which means, that if the light photon had momentum p, the change of momentum is also p. On the other side a white material would in fact not absorb the energy, but change the direction on the photons, which would imply a change in momentum of 2p. Now just remember, that F=dp/dt and you have your answer.

I think you are asking about nonlinear optics. For sufficiently high powered light, the index of refraction may change.

I can clarify that the force of light does not change with absorption or reflection. The force of light is dependent on its energy, which is determined by its wavelength and intensity. When light is absorbed, its energy is transferred to the absorbing material, causing it to heat up or undergo a chemical reaction. However, this does not change the force of the light itself. Similarly, when light is reflected, its energy is not altered but rather redirected off the surface. Therefore, the force of light remains constant regardless of whether it is absorbed or reflected. The equation W = Fv is applicable for calculating the work done by light, but it does not directly relate to the force of light itself. I hope this helps clarify your confusion.

## What is light absorption and reflection?

Light absorption is the process by which an object takes in and absorbs certain wavelengths of light, while reflecting others. Light reflection is the process by which an object bounces off or reflects certain wavelengths of light instead of absorbing them.

## How does the force of light change with absorption?

The force of light is a measure of the amount of energy carried by light particles, known as photons. When light is absorbed by an object, the energy of the photons is transferred to the particles of the object, causing them to vibrate and create heat. This can result in a decrease in the force of light as some of its energy is transferred to the object.

## How does the force of light change with reflection?

When light is reflected by an object, the energy of the photons remains intact and is not transferred to the object. This means that the force of light remains constant during reflection. However, the direction of the force may change as the angle of reflection is different from the angle of incidence.

## Does the color of an object affect light absorption and reflection?

Yes, the color of an object can affect the amount of light absorption and reflection it experiences. Objects that appear white reflect most of the wavelengths of light, while objects that appear black absorb most of the wavelengths. This is due to the different properties of the object's surface and how they interact with light.

## How do materials differ in their ability to absorb and reflect light?

The ability of a material to absorb and reflect light depends on its physical properties, such as density, texture, and color. Some materials, like metals, are good reflectors and poor absorbers of light, while others, like dark colored fabrics, are good absorbers and poor reflectors. The composition and structure of a material also play a role in its light absorption and reflection abilities.

• Optics
Replies
2
Views
1K
• Optics
Replies
0
Views
341
• Optics
Replies
64
Views
2K
• Optics
Replies
7
Views
1K
• Optics
Replies
10
Views
1K
• Optics
Replies
3
Views
3K
• Optics
Replies
8
Views
2K
• Optics
Replies
7
Views
1K
• Optics
Replies
5
Views
1K
• Optics
Replies
41
Views
3K