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What you will learn in Optics

1. Reflection and Plane Mirrors
The angle of incidence equals the angle of reflection — measured from the normal — and that one rule fixes everything a plane mirror does.
2. Curved Mirrors
Bend the mirror and the image starts moving: concave mirrors converge light and can form real images, convex mirrors never do.
3. Refraction and Snell's Law
Light changes speed crossing into a new medium, and changing speed is what makes it change direction.
4. Refractive Index
Refractive index is not a label on a table — it is the factor by which a material slows light down, and it predicts the bend.
5. Lenses and Ray Diagrams
Three rays with three rules locate any image a thin lens forms — and the lens equation agrees with them every time.
6. Focal Length
Hold the object still and change only the focal length: one number decides whether an image is real or virtual, magnified or shrunk.
7. Total Internal Reflection and Fibre Optics
Past the critical angle the refracted ray stops existing altogether — and an optical fibre is that fact, stretched out over kilometres.
8. Dispersion and the Prism
Refractive index depends slightly on wavelength, so a single ray of white light leaves a prism as a spectrum.
9. The Microscope and the Telescope
Two converging lenses in a tube: one makes a real image, the other is a magnifying glass held to it. That is a microscope or a telescope, depending only on where the object is.

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1. Reflection and Plane Mirrors
The angle of incidence equals the angle of reflection — measured from the normal — and that one rule fixes everything a plane mirror does.
2. Curved Mirrors
Bend the mirror and the image starts moving: concave mirrors converge light and can form real images, convex mirrors never do.
3. Refraction and Snell's Law
Light changes speed crossing into a new medium, and changing speed is what makes it change direction.
4. Refractive Index
Refractive index is not a label on a table — it is the factor by which a material slows light down, and it predicts the bend.
5. Lenses and Ray Diagrams
Three rays with three rules locate any image a thin lens forms — and the lens equation agrees with them every time.
6. Focal Length
Hold the object still and change only the focal length: one number decides whether an image is real or virtual, magnified or shrunk.
7. Total Internal Reflection and Fibre Optics
Past the critical angle the refracted ray stops existing altogether — and an optical fibre is that fact, stretched out over kilometres.
8. Dispersion and the Prism
Refractive index depends slightly on wavelength, so a single ray of white light leaves a prism as a spectrum.
9. The Microscope and the Telescope
Two converging lenses in a tube: one makes a real image, the other is a magnifying glass held to it. That is a microscope or a telescope, depending only on where the object is.