Interactive Ray Optics Simulator
Explore image formation by spherical mirrors and lenses. Adjust the parameters below to see real-time ray diagrams and calculations based on Cartesian Sign Conventions.
Placed on the left (-ve x-axis)
Distance to principal focus
Calculated Results
Image Dist (v)
-- cm
Image Height (h')
-- cm
Magnification (m)
--
Nature of Image
--
Chapter 10: Light - Reflection and Refraction
Comprehensive Study Notes & CBSE Exam Quiz
1. Reflection of Light
A highly polished surface, such as a mirror, reflects most of the light falling on it. The laws of reflection state that:
- The angle of incidence is equal to the angle of reflection.
- The incident ray, the normal to the mirror at the point of incidence, and the reflected ray, all lie in the same plane.
2. Spherical Mirrors
The reflecting surface of a spherical mirror forms a part of a sphere. There are two main types:
Concave Mirror
Convex Mirror
- Concave Mirror: Reflecting surface is curved inwards. It converges light and is used in torches, vehicle headlights, shaving mirrors, and by dentists.
- Convex Mirror: Reflecting surface is curved outwards. It diverges light and is commonly used as rear-view mirrors in vehicles because it always gives an erect, diminished image and provides a wider field of view.
🎮 Mini-Game: Mirror Match!
Question: I am used as a rear-view mirror in cars because I give a wider field of view. Which mirror am I?
3. Sign Convention & Mirror Formula
We follow the New Cartesian Sign Convention where the pole (P) is the origin. Distances to the right of the pole are positive (+ve) and to the left are negative (-ve). Distances above the principal axis are positive (+ve).
Magnification (m) is the ratio of the height of the image (h') to the height of the object (h).
Formula: m = h'/h = -v/u.
4. Refraction of Light
When light travels obliquely from one medium to another, the direction of propagation changes. This is called refraction. It happens due to a change in the speed of light.
- Snell's Law: The ratio of sine of angle of incidence to the sine of angle of refraction is constant (sin i / sin r = constant).
- Refractive Index (n): It represents the extent of the change in direction and is linked to the relative speed of light. Absolute refractive index, n = Speed of light in vacuum (c) / Speed of light in medium (v).
5. Spherical Lenses
A transparent material bound by two surfaces, of which one or both are spherical, forms a lens.
Convex Lens
Concave Lens
- Convex Lens (Converging): Thicker in the middle. Converges parallel rays of light to a principal focus.
- Concave Lens (Diverging): Thicker at the edges. Diverges parallel rays of light.
6. Power of a Lens
The degree of convergence or divergence of light rays achieved by a lens is its power (P). It is the reciprocal of its focal length (in meters).
- Formula: P = 1 / f
- Unit: Dioptre (D). 1 D is the power of a lens whose focal length is 1 meter.
- The power of a convex lens is positive, and the power of a concave lens is negative.
🎮 Mini-Game: Calculate the Power!
A doctor prescribes a corrective convex lens with a focal length of 0.5 meters. What is the power of this lens?
📝 CBSE Board Exam Mastery Quiz
Test your knowledge with 10 actual questions from the last 5 years' CBSE board exams. You need 70% to pass and you have a maximum of 2 attempts.
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