Definition:

Ray Optics (Geometrical Optics) deals with the study of light in terms of rays and the formation of images by reflection and refraction.

• It ignores wave nature of light.

• Focuses on mirrors, lenses, prisms, and optical devices.

📌 1️⃣ Laws of Reflection

1. Angle of incidence = Angle of reflection

2. Incident ray, reflected ray, and normal lie in the same plane

Application: Plane mirrors, periscopes, kaleidoscopes

📌 2️⃣ Laws of Refraction

1. Ray bends when it passes from one medium to another

2. Incident ray, refracted ray, and normal lie in same plane

Key Concept: Bending depends on refractive index of media.

📌 3️⃣ Lenses

• Convex Lens → Converging lens → can form real and virtual images

• Concave Lens → Diverging lens → always forms virtual image

Key Uses:

• Magnifying glasses (convex lens)

• Correcting vision defects (myopia, hypermetropia)

• Cameras and projectors

📌 4️⃣ Mirrors

• Plane Mirror → Virtual, erect, same size image

• Concave Mirror → Converging, can form real or virtual images

• Convex Mirror → Diverging, virtual, diminished image

Applications: Rearview mirrors, shaving mirrors, telescopes

📌 5️⃣ Refraction through Prisms

• Prism disperses light into spectrum (colors)

• Applications: Spectrometers, rainbows, binoculars

📌 6️⃣ Optical Instruments

1. Human Eye

   • Lens changes shape → focuses light on retina

   • Corrected using glasses or contact lenses for vision defects

2. Microscope

   • Uses objective and eyepiece lenses

   • Produces highly magnified real images of small objects

3. Telescope

   • Astronomical telescope: observes distant objects

   • Uses objective and eyepiece lenses to form magnified images

4. Camera

   • Lens focuses light on film or sensor

   • Forms real, inverted images

5. Magnifying Glass

   • Convex lens → forms virtual, magnified image

   • Used for reading small text

📌 Important Concepts

• Real image → formed on screen, inverted

• Virtual image → cannot be projected, erect

• Lens formula and mirror formula → relate object, image, and focal length

• Magnification → ratio of image size to object size

🌟 Quick Notes for Revision

1. Ray optics → study light as rays

2. Reflection & Refraction → image formation

3. Mirrors & Lenses → real vs virtual images

4. Prisms → dispersion and deviation of light

5. Optical Instruments → magnification and image formation

6. Applications → daily life, medical, telescopes, microscopes