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Cause and Effect — Curving Light
How Shape Decides the Image
A surface is curved
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Concave / convex mirror
Converges or diverges reflected light.
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Convex / concave lens
Converges or diverges light passing through.
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Image can be enlarged, diminished, erect, or inverted
Mind Map
Mirrors & Lenses
Reflecting and bending light
10.1
Spherical Mirrors
Concave curves inwards; convex curves outwards.
10.2
Images Formed
Concave: enlarged then inverted; convex: always small, erect.
10.3
Laws of Reflection
i equals r; incident ray, normal, reflected ray in one plane.
10.4
What Is a Lens?
Convex converges light; concave diverges it.
Key Terms and Definitions
- Plane mirror
- A flat mirror that forms an erect, same-size image.
- Spherical mirror
- A mirror whose reflecting surface is part of a sphere.
- Concave mirror
- A spherical mirror with a surface that curves inwards.
- Convex mirror
- A spherical mirror with a surface that curves outwards.
- Enlarged image
- An image larger than the object.
- Diminished image
- An image smaller than the object.
- Erect image
- An image the same way up as the object.
- Inverted image
- An image upside down compared with the object.
- Incident ray
- The ray of light that falls on the mirror.
- Reflected ray
- The ray of light that comes back from the mirror.
- Normal
- The line at 90° to the mirror at the point of incidence.
- Angle of incidence
- The angle between the incident ray and the normal.
- Angle of reflection
- The angle between the reflected ray and the normal.
- Lens
- A transparent piece of glass or plastic with curved surfaces.
- Convex lens
- A lens thicker in the middle; converges light.
- Concave lens
- A lens thicker at the edges; diverges light.
