Reflection from Surfaces (AQA GCSE Physics)

Specular & Diffuse Reflection

Specular Reflection

• Specular reflection is defined as:

  Reflection from a smooth surface in a single direction

• When light reflects off a smooth surface, such as a mirror, specular reflection occurs

  • This is what gives a mirror its shiny appearance

• This is why a reflection can be seen clearly in a mirror

• In this case, the angle of reflection r is equal to the angle of incidence i

When reflecting off a mirror, the specular reflection occurs. The angle of incidence is equal to the angle of reflection

Diffuse Reflection

• Diffuse reflection is defined as:

  Reflection from a rough surface causes scattering

• When light reflects off a rough surface, which applies to the majority of surfaces, diffuse reflection occurs

  • This is what gives objects a dull or matt appearance

• This is why a reflection cannot be seen clearly from a table surface, for example

  • Even though a table's surface may look smooth from afar, it is actually made up of many tiny ridges which the light rays are scattered off

• When light scatters, it leaves the surface in all directions

When light is reflected from the majority of surfaces it is scattered – a process known as diffuse reflection