Light Reflection and Refraction Class 10 Science — Revision Notes
This chapter examines how light behaves when it encounters surfaces and different media. Students learn about mirrors, lenses, and the laws governing refle
TL;DR: This chapter examines how light behaves when it encounters surfaces and different media. Students learn about mirrors, lenses, and the laws governing…
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This chapter examines how light behaves when it encounters surfaces and different media. Students learn about mirrors, lenses, and the laws governing refle
Reflection of Light
- Law of Reflection: angle of incidence equals angle of reflection
- Normal is perpendicular line at point of incidence
- Plane mirror produces virtual, erect, same-size image
- Curved mirrors: concave (converging) and convex (diverging)
Curved Mirrors
- Focal length f = R/2 where R is radius of curvature
- Mirror formula: 1/f = 1/v + 1/u
- Magnification m = -v/u = h'/h
- Concave mirror used in torches, telescopes; convex in vehicle mirrors
Refraction of Light
- Refraction: bending of light when entering different medium
- Snells Law: n1 sin θ1 = n2 sin θ2
- Refractive index n = c/v where c is light in vacuum, v in medium
- Critical angle: angle beyond which total internal reflection occurs
Lenses
- Convex lens converges light rays to focal point
- Concave lens diverges light rays appearing to come from focal point
- Lens formula: 1/f = 1/v + 1/u (same as mirrors)
- Power of lens P = 1/f in diopters (D)
Key Terms
- Focal Length: Distance from lens/mirror to focal point where light rays converge
- Real Image: Image formed where light rays actually converge, inverted and magnified
- Virtual Image: Image formed where light rays appear to come from, erect and diminished
Frequently Asked Questions
What is the difference between reflection and refraction?
Reflection is bouncing of light from surface following law of reflection. Refraction is bending of light entering different medium following Snells law.
How do concave and convex lenses differ?
Concave lens diverges light rays and forms virtual images. Convex lens converges light rays and can form real or virtual images depending on object position.
More Class 10 Science Revision Notes
- Chemical Reactions and Equations
- Acids Bases and Salts
- Metals and Non-metals
- Carbon and its Compounds
- Life Processes
- Control and Coordination
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