Terminology of Reflection
Understanding terms like incident ray, reflected ray, normal, angle of incidence, and angle of reflection.
What is Terminology of Reflection?
The ray of light that strikes a surface.
Key formula / rule: Angle of Incidence
Key points
- Define and identify the incident ray, reflected ray, and normal.
- Understand the concepts of angle of incidence and angle of reflection.
- Differentiate between the angles measured with respect to the normal and the surface.
Common exam trap
Confusing the angle of incidence/reflection with the angle made with the surface.
Definitions
- Term
Incident Ray
- Meaning
The ray of light that strikes a surface.
- Term
Reflected Ray
- Meaning
The ray of light that bounces back from the surface after striking it.
- Term
Normal
- Meaning
An imaginary line drawn perpendicular to the reflecting surface at the point of incidence.
- Term
Point of Incidence
- Meaning
The point on the reflecting surface where the incident ray strikes.
- Term
Angle of Incidence (∠i)
- Meaning
The angle between the incident ray and the normal.
- Term
Angle of Reflection (∠r)
- Meaning
The angle between the reflected ray and the normal.
Learning objectives
Define and identify the incident ray, reflected ray, and normal.
Understand the concepts of angle of incidence and angle of reflection.
Differentiate between the angles measured with respect to the normal and the surface.
Formulae
- Name
Angle of Incidence
- Note
Angle between incident ray and the normal.
- Expression
∠i
- Name
Angle of Reflection
- Note
Angle between reflected ray and the normal.
- Expression
∠r
- Name
Law of Reflection (Equality of Angles)
- Note
The angle of incidence is equal to the angle of reflection.
- Expression
∠i = ∠r
Prerequisites
Basic understanding of light as a ray.
Concept of a straight line and perpendicularity.
Common mistakes
Confusing the angle of incidence/reflection with the angle made with the surface.
Not drawing or visualizing the normal correctly.
Assuming reflection only happens with mirrors; it occurs with any smooth surface.
Keywords
Reflection
Incident Ray
Reflected Ray
Normal
Angle of Incidence
Angle of Reflection
Point of Incidence
Laws of Reflection
Optics
Practice preview
According to the laws of reflection, the angle of incidence is always equal to which angle?…
easy
In the context of reflection, what is the angle between the incident ray and the normal called?…
easy
Which of the following terms describes the line perpendicular to the reflecting surface at the point of incidence?…
easy