# Incident light angle brightness

• pikapika!
In summary, the brightness of light hitting a surface is affected by the angle at which it hits. The relationship between angle and brightness is not linear and can be calculated using the cosine of the angle. This is due to the larger surface area that the beam interacts with at higher angles. Additionally, there is an inverse-square dependence which is only significant when the light source is very far from the surface.

#### pikapika!

when light hits a surface at an angle. it is darker if it hits it at higher angle(facing away) than at a lower angle(facing towards). 1

Is there a formula for the brightness.The relationship of angle to brightness does not look linear.

http://www.vam.ac.uk/vastatic/microsites/1384_leonardo/animated_illustrations/view/?movie=light" [Broken]1

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The brightness would go like cos of the angle.

Is this only because the greater the angle, the greater the surface area that the beam interacts with? Or are there other factors?

It is just that Intensity = Power/area

There is also an inverse-square dependence, which is negligible if (for example) a point-like source is very far from the surface.

## 1. What is incident light angle brightness?

Incident light angle brightness refers to the amount of light that strikes an object at a specific angle. It is a measure of how bright the object appears to an observer at that angle.

## 2. How does the angle of incident light affect brightness?

The angle of incident light can greatly affect brightness. When the incident light is perpendicular to the surface, the object appears brightest. As the angle of incident light deviates from perpendicular, the brightness decreases.

## 3. What is the relationship between incident light angle and shadows?

The angle of incident light also affects the appearance of shadows. When the incident light is at a low angle, it creates longer shadows, while a high angle of incident light creates shorter shadows.

## 4. What factors impact incident light angle brightness?

The primary factors that impact incident light angle brightness are the intensity and direction of the light source, the reflective properties of the object, and the surface texture of the object.

## 5. How is incident light angle brightness measured?

Incident light angle brightness can be measured using a photometer, which detects the intensity of light at a specific angle. It can also be measured using a spectrophotometer, which measures the amount of light reflected off a surface at different angles.