This document provides an overview of reflection and refraction of light by Vivek Sawhney, a physics teacher. It covers the basic laws and concepts related to reflection by plane and spherical mirrors, including image formation. It also discusses refraction through spherical lenses and glass slabs. Key terms like focal length, radius of curvature, and refractive index are defined. Ray diagrams demonstrate how light bends when reflecting or refracting. Real-world applications of mirrors and lenses are also mentioned.

1. Prepared by: Vivek
Sawhney, PGT Physics,
KV Jalgaon
Light-
Reflection and
Refraction
Class 10
Prepared By : Vivek Sawhney, PGT PHYSICS, KV,
JALGAON

2. Reflection of Light
– When light falls on a highly polished surface like
a mirror most of the light is sent back into the
same medium. This process is called reflection
of light.
Prepared By : Vivek Sawhney, PGT PHYSICS, KV, JALGAON

3. Regular and Diffuse Reflection
Prepared By : Vivek Sawhney, PGT PHYSICS, KV, JALGAON

4. Laws of Reflection of Light
– i) The angle of incidence is equal to the angle of reflection.
– The incident ray, the reflected ray and the normal to the mirror at the
point of incidence all lie in the same plane.
Prepared By : Vivek Sawhney, PGT PHYSICS, KV, JALGAON

5. Real and Virtual Images
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6. Prepared By : Vivek Sawhney, PGT PHYSICS, KV, JALGAON

7. Image formed by Plane Mirror
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8. Characteristics of image formed
by plane mirror
– Plane mirror forms an erect image.
– It forms a virtual image.
– Size of the image is same as that of the object.
– Image is formed at the same distance behind the
mirror as the object stands in front of it.
– Image formed is a laterally inverted image i.e.,
right hand side of the object seems to be the left
hand side and vice-versa.
Prepared By : Vivek Sawhney, PGT PHYSICS, KV, JALGAON

9. Spherical Mirrors
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10. Concave and Convex Spherical
Mirror
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11. Basic Terms
– Center of Curvature The point in the centre of the mirror that
passes through the curve of the mirror and has the same
tangent and curvature at that point.
– Radius of Curvature It’s the linear distance between Pole
and the Center of curvature.
– Principal axis The imaginary line passing through the optical
center and the center of curvature of any lens or a spherical
mirror.
Prepared By : Vivek Sawhney, PGT PHYSICS, KV, JALGAON

12. – Pole The midpoint of the spherical mirror.
– Aperture An aperture of a mirror or lens is a point from
which the reflection of light actually happens. It also gives the
size of the mirror.
– Principal Focus Principal Focus can also be called Focal
Point. It’s on the axis of a mirror or lens wherein rays of light
parallel to the axis converge or appear to converge after
reflection or refraction.
Prepared By : Vivek Sawhney, PGT PHYSICS, KV, JALGAON

13. Prepared By : Vivek Sawhney, PGT PHYSICS, KV, JALGAON

14. Rules for Drawing Ray
Diagrams
– Rule 1: incident ray passing through principal focus, after
reflection get parallel to principal axis
Prepared By : Vivek Sawhney, PGT PHYSICS, KV, JALGAON

15. – Rule 2: the incident ray travelling parallel to principal axis, after
reflection passed through principal focus.
Prepared By : Vivek Sawhney, PGT PHYSICS, KV, JALGAON

16. – Rule 3: the incident ray passing through centre of curvature is
reflected back along the same path.
Prepared By : Vivek Sawhney, PGT PHYSICS, KV, JALGAON

17. – Rule 4: the ray incident obliquely on a mirror surface, get
reflected obliquely as per the laws of reflection.
–
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18. Ray Diagrams- Concave Mirrors
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19. Prepared By : Vivek Sawhney, PGT PHYSICS, KV, JALGAON

20. Ray Diagrams– Convex Mirrors
Prepared By : Vivek Sawhney, PGT PHYSICS, KV, JALGAON

21. Sign Conventions
Prepared By : Vivek Sawhney, PGT PHYSICS, KV, JALGAON

22. Mirror Formula
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23. Uses of Concave Mirrors
Prepared By : Vivek Sawhney, PGT PHYSICS, KV, JALGAON

24. Uses of Concave Mirrors
– Concave mirrors are commonly used in torches, search-lights and vehicles
headlights to get powerful parallel beams of light.
– They are often used as shaving mirrors to see a larger image of the face.
– The dentists use concave mirrors to see large images of the teeth of
patients.
–
– Large concave mirrors are used to concentrate sunlight to produce heat in
solar furnaces.
Prepared By : Vivek Sawhney, PGT PHYSICS, KV, JALGAON

25. Uses of Convex Mirrors
– Convex mirrors are commonly used as rear-view (wing)
mirrors in vehicles. These mirrors are fitted on the sides
of the vehicle, enabling the driver to see traffic behind
him/her to facilitate safe driving. Convex mirrors are
preferred because they always give an erect, though
diminished, image. Also, they have a wider field of view
as they are curved outwards. Thus, convex mirrors
enable the driver to view much larger area than would be
possible with a plane mirror.
Prepared By : Vivek Sawhney, PGT PHYSICS, KV, JALGAON

26. Fun with Lasers
– Click here to Watch
Prepared By : Vivek Sawhney, PGT PHYSICS, KV, JALGAON

27. Refraction of Light
Prepared By : Vivek Sawhney, PGT PHYSICS, KV, JALGAON

28. Refraction of Light-Amazing
Activities
– Click here to Watch
Prepared By : Vivek Sawhney, PGT PHYSICS, KV, JALGAON

29. – Refraction is the bending of light (it also happens with
sound, water and other waves) as it passes from one
transparent substance into another.
– This bending by refraction makes it possible for us to
have lenses, magnifying glasses, prisms and rainbows.
– Even our eyes depend upon this bending of light.
Without refraction, we wouldn’t be able to focus light
onto our retina.
Prepared By : Vivek Sawhney, PGT PHYSICS, KV, JALGAON

30. Laws of Refraction
– The incident ray, reflected ray and the normal, to the
interface of any two given mediums; all lie in the same
plane.
– The ratio of the sine of the angle of incidence and sine
of the angle of refraction is constant.
Prepared By : Vivek Sawhney, PGT PHYSICS, KV, JALGAON

31. Prepared By : Vivek Sawhney, PGT PHYSICS, KV, JALGAON

32. Refractive Index
– Refractive index, also called index of refraction, measure of the
bending of a ray of light when passing from one medium into
another.
– The refractive index n is defined as the ratio of the sine of the
angle of incidence to the sine of the angle of refraction;
– i.e., n = sin i / sin r.
– Refractive index is also equal to the velocity of light c of a given
wavelength in empty space divided by its velocity v in a
substance, or
– n = c/v
Prepared By : Vivek Sawhney, PGT PHYSICS, KV, JALGAON

33. Rarer and Denser Medium
– A medium in which speed of light is more is known as
optically rarer medium and a medium in which speed of
light is less is said to be optically denser medium. For
example in air and water, air is rarer and water is a
denser medium.
Prepared By : Vivek Sawhney, PGT PHYSICS, KV, JALGAON

34. Rules for bending of Light
– when a ray of light passes from a rarer medium to a denser medium,
the ray of light bends towards the normal... this is bcz the velocity of
light decrease as the rays go from rarer to denser medium..
– when a ray of light passes from a denser medium to a rarer
medium,the ray of light bends away from the normal ....
Prepared By : Vivek Sawhney, PGT PHYSICS, KV, JALGAON

35. Refraction of Light through a
Glass Slab
Prepared By : Vivek Sawhney, PGT PHYSICS, KV, JALGAON

36. Refraction of Light through a
Glass Slab
– click here to watch
Prepared By : Vivek Sawhney, PGT PHYSICS, KV, JALGAON

37. Spherical Lenses
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38. Terms related to Spherical
Lenses
Prepared By : Vivek Sawhney, PGT PHYSICS, KV, JALGAON

39. – i) Optical center is defined as the point on the lens which
is on the principal axis and the light ray doesn't deflect
when passes through it.
– (ii) Centre of curvature is defined as the center of the
surface of sphere of which the lens is a part. Since, a
lens has two surfaces, so the lens has two centers of
curvatures.
– (iii) Principal axis is defined as the straight lines
passing through center of curvature
– . (iv)Aperture is defined as the diameter of the boundary
of the circular lens.
– (v) Principal focus is defined as the point where beam of
light parallel to principal axis, either converges or
diverges after refraction
– (vi) Focal length is defined as the distance between the
Prepared By : Vivek Sawhney, PGT PHYSICS, KV, JALGAON

40. Principal Focus
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41. Rules for drawing Ray Diagrams
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42. Prepared By : Vivek Sawhney, PGT PHYSICS, KV, JALGAON

43. Ray Diagrams for Convex Lens
Prepared By : Vivek Sawhney, PGT PHYSICS, KV, JALGAON

44. Characteristics of the Image
formed
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45. Concave Lens
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46. Prepared By : Vivek Sawhney, PGT PHYSICS, KV, JALGAON

47. Prepared By : Vivek Sawhney, PGT PHYSICS, KV, JALGAON

48. Power of a Lens
– The power of a lens is defined as the reciprocal of its
focal length in meters,
– or D = 1/f,
– where D is the power in diopters and f is the focal length
in meters.
– The diopter is the unit of measure for the refractive
power of a lens.
Prepared By : Vivek Sawhney, PGT PHYSICS, KV, JALGAON

49. Power of combination of Lenses
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50. Prepared By : Vivek Sawhney, PGT PHYSICS, KV, JALGAON