In this note, we are going to learn about Lambert Cosine Law of Illumination. Welcome to **Poly Notes Hub**, a leading destination for **engineering notes** for diploma and degree engineering students.

Author Name: **Arun Paul**.

## Lambert Cosine Law of Illumination

**Lambert’s Cosine Law**, also known as Lambert’s Cosine Emission Law or Lambert’s Law of Cosines, defines the angular distribution of radiation emitted by an ideal diffuse surface. This law states that the intensity of radiation or light emitted from a surface is proportional to the cosine of the angle formed between the emitted light’s direction and the surface normal.

**Mathematically, Lambert’s Cosine Law is expressed as:**

I(θ)=I_{0}cos(θ)

where:

- I(θ) = intensity of light emitted at an angle θ from the normal.
- I
_{0}= intensity of light emitted perpendicular to the surface (at θ = 0). - θ = angle between the emitted light direction and the normal to the surface.

## Applications of Lambert Cosine Law

**Here we have listed some Lambert’s Cosine Laws Applications –**

- Lambert’s Cosine Law applies to perfect diffuse emitters or Lambertian surfaces, which emit light evenly in all directions, with strength decreasing as angle increases.
- It is critical in estimating light distributions for many lighting applications, ensuring uniform lighting in settings such as photographic studios, theaters, and architectural spaces.
- The rule is used in rendering algorithms to create realistic lighting and shading effects on surfaces.