# 10-LIGHT

Views:

Category: Education

## Presentation Description

By: akshitakatyal16 (40 month(s) ago)

By: vamsikrishna716 (50 month(s) ago)

## Presentation Transcript

### CHAPTER – 10 LIGHT : REFLECTION AND REFRACTION:

CHAPTER – 10 LIGHT : REFLECTION AND REFRACTION Class :- X Subject :- SCIENCE Name :- Manish Yadav Add me as friend on facebook cutemanish66@gmail.com

### LAWS OF RELECTION OF LIGHT:

LAWS OF RELECTION OF LIGHT 1) The angle of incidence is equal to the angle of reflection. 2) The incident ray, reflected ray and normal to the mirror at the point of incidence all lie in the same plane. i r Incident ray Reflected ray Normal Plane mirror

### FORMATION OF IMAGE BY A PLANE MIRROR i) The image is virtual. ii) The image is erect. iii) The image is same size as the object. iv) The image is as far behind the mirror as the object is in front of it. v) The image is laterally inverted. :

FORMATION OF IMAGE BY A PLANE MIRROR i ) The image is virtual. ii) The image is erect. iii) The image is same size as the object. iv) The image is as far behind the mirror as the object is in front of it. v) The image is laterally inverted. Object Image Normal Normal Eye Plane mirror Object distance Image distance i r i r

### TERMS USED IN THE STUDY OF CONCAVE MIRRORS XY - Principal axis CP - Radius of curvature P - Pole F - Principal focus C - Centre of curvature PF - Focal length :

TERMS USED IN THE STUDY OF CONCAVE MIRRORS XY - Principal axis CP - Radius of curvature P - Pole F - Principal focus C - Centre of curvature PF - Focal length M’ M X Y C F P . .

### RULES FOR OBTAINING IMAGES FORMED BY CONCAVE MIRRORS:

RULES FOR OBTAINING IMAGES FORMED BY CONCAVE MIRRORS 1) A ray of light parallel to the principal axis after reflection from a concave mirror passes through the focus. C F P M M’ Y X . .

### 2) A ray of light passing through the focus after reflection from a concave mirror goes parallel to the principal axis.:

2) A ray of light passing through the focus after reflection from a concave mirror goes parallel to the principal axis. C F P M M’ Y X . .

### 3) A ray of light passing through the centre of curvature after reflection from a concave mirror is reflected back along the same path.:

3) A ray of light passing through the centre of curvature after reflection from a concave mirror is reflected back along the same path. C F P M M’ Y X . .

### 4) A ray of light which is incident at the pole of a concave mirror is reflected back making the same angle with the principal axis.:

4) A ray of light which is incident at the pole of a concave mirror is reflected back making the same angle with the principal axis. M i r F C P M’ Y X . .

### IMAGES FORMED BY CONCAVE MIRROR 1) When the object is at infinity, the image is formed at the focus, is highly diminished, real and inverted.:

IMAGES FORMED BY CONCAVE MIRROR 1) When the object is at infinity, the image is formed at the focus, is highly diminished, real and inverted. B C F P A M’ M . .

### 2) When the object is beyond the centre of curvature, the image is formed between the focus and the centre of curvature, is diminished, real and inverted.:

2) When the object is beyond the centre of curvature, the image is formed between the focus and the centre of curvature, is diminished, real and inverted. B P A A’ B’ M M’ . . F C

### 3) When the object is at the centre of curvature, the image is formed at the centre of curvature, is of the same size as the object, real and inverted. :

3) When the object is at the centre of curvature, the image is formed at the centre of curvature, is of the same size as the object, real and inverted. P F C A B A’ B’ M M’

### 4) When the object is between centre of curvature and focus, the image is formed beyond the centre of curvature, is enlarged, real and inverted.:

4) When the object is between centre of curvature and focus, the image is formed beyond the centre of curvature, is enlarged, real and inverted. C B F P B’ A’ M M’ A . .

### 5) When the object is at the focus, the image is formed at infinity, is highly enlarged, real and inverted.:

5) When the object is at the focus, the image is formed at infinity, is highly enlarged, real and inverted. P F C B M M’ A .

### 6) When the object is between pole and focus, the image is formed behind the mirror, is enlarged, virtual and erect.:

6) When the object is between pole and focus, the image is formed behind the mirror, is enlarged, virtual and erect. F B A P A’ B’ C M M’ . .

### TERMS USED IN THE STUDY OF CONVEX MIRRORS XY - Principal axis CP - Radius of curvature P - Pole F - Principal focus C - Centre of curvature PF - Focal length:

TERMS USED IN THE STUDY OF CONVEX MIRRORS XY - Principal axis CP - Radius of curvature P - Pole F - Principal focus C - Centre of curvature PF - Focal length F C P X Y M M’

### RULES FOR OBTAINING IMAGES FORMED BY CONVEX MIRROR 1) A ray of light parallel to the principal axis after reflection from a convex mirror appears to come from the focus behind the mirror.:

RULES FOR OBTAINING IMAGES FORMED BY CONVEX MIRROR 1) A ray of light parallel to the principal axis after reflection from a convex mirror appears to come from the focus behind the mirror. P F C M M’ Y X

### 2) A ray of light directed towards the focus of a convex mirror after reflection goes parallel to the principal axis.:

2) A ray of light directed towards the focus of a convex mirror after reflection goes parallel to the principal axis. P F C Y X M M’

### 3) A ray of light directed towards the centre of curvature of a convex mirror after reflection goes back along the same path.:

3) A ray of light directed towards the centre of curvature of a convex mirror after reflection goes back along the same path . P F C X Y M M’

### 4) A ray of light which is incident at the pole of a convex mirror is reflected back making the same angle with the principal axis. :

4) A ray of light which is incident at the pole of a convex mirror is reflected back making the same angle with the principal axis. F C P i r Y X M M’

### IMAGES FORMED BY CONVEX MIRROR 1) When the object is at infinity, the image is formed at the focus behind the mirror, is highly diminished , virtual and erect.:

IMAGES FORMED BY CONVEX MIRROR 1) When the object is at infinity, the image is formed at the focus behind the mirror, is highly diminished , virtual and erect. B A P F C M M’

### 2) When the object is between infinity and the pole of the mirror, the image is formed between the pole and focus behind the mirror, is diminished, virtual and erect.:

2) When the object is between infinity and the pole of the mirror, the image is formed between the pole and focus behind the mirror, is diminished, virtual and erect. A P F C B M M’

### NEW CARTESIAN SIGN CONVENTION FOR SPHERICAL MIRRORS:

NEW CARTESIAN SIGN CONVENTION FOR SPHERICAL MIRRORS Direction of incident light Distance towards the left ( - ve ) Distance towards the right ( + ve ) Height downwards ( -ve ) Height upwards ( +ve ) Concave mirror Object Image

### MIRROR FORMULA FOR SPHERICAL MIRRORS:

MIRROR FORMULA FOR SPHERICAL MIRRORS The mirror formula for spherical mirrors is the relationship between the object distance, image distance and focal length. The mirror formula is expressed as :- 1 1 1 v u f MAGNIFICATION PRODUCED BY SPHERICAL MIRRORS With respect to the object size and image size, magnification is the ratio of the size of the image to the size of the object. Height of the image h’ Magnification = m = Height of the object h The magnification is also related to the object distance and image distance. It can be expressed as :- h’ v Magnification m = = - h u

### REFRACTION OF LIGHT:

REFRACTION OF LIGHT When light travels obliquely from one transparent medium into another it gets bent. This bending of light is called refraction of light. When light travels from a rarer medium to a denser medium, it bends towards the normal. When light travels from a denser medium to a rarer medium to a rarer medium, it bends away from the normal. Denser medium Rarer medium Rarer medium Denser medium Normal Normal

### REFRACTION OF LIGHT THROUGH A RECTANGULAR GLASS SLAB:

REFRACTION OF LIGHT THROUGH A RECTANGULAR GLASS SLAB When a ray of light passes through a rectangular glass slab, it gets bent twice at the air- glass interface and at the glass- air interface. The emergent ray is parallel to the incident ray but is displaced through a distance. i r Normal Incident ray Emergent ray Refracted ray Glass Air Normal i r Glass Air Rectangular glass slab

### LAWS OF REFRACTION OF LIGHT:

LAWS OF REFRACTION OF LIGHT 1) The incident ray, the refracted ray and the normal to the interface of two transparent media at the point of incidence, all lie in the same plane. 2) The ratio of the sin of angle of incidence to the sin of angle of refraction is a constant, for the light of a given colour and for the given pair of media.( This law is also known as Snell`s law of refraction.) sin i constant sin r REFRACTIVE INDEX The absolute refractive index of a medium is the ratio of the speed of light in air or vacuum to the speed of light in medium. Speed of light in air or vacuum Refractive index = Speed of light in the medium n = C V The relative refractive index of a medium 2 with respect to a medium 1 is the ratio of the speed of light in medium 1 to the speed of light in medium 2. n 21 Speed of light in medium 1 = Speed of light in medium 2

### SPHERICAL LENSES A convex lens is thicker in the middle and thinner at the edges. A concave lens is thinner at the middle and thicker at the edges. :

SPHERICAL LENSES A convex lens is thicker in the middle and thinner at the edges. A concave lens is thinner at the middle and thicker at the edges. Convex lens Concave lens

### TERMS USED IN THE STUDY OF CONVEX LENS XY - Principal axis F2 - Principal focus O - Optical centre OF2 - Focal length :

TERMS USED IN THE STUDY OF CONVEX LENS XY - Principal axis F 2 - Principal focus O - Optical centre OF 2 - Focal length F 1 F 2 2F 1 2F 2 O X Y

### IMAGES FORMED BY CONVEX LENS 1) When the object is at infinity, the image is formed at the focus F2, it is highly diminished, real and inverted.:

IMAGES FORMED BY CONVEX LENS 1) When the object is at infinity, the image is formed at the focus F 2 , it is highly diminished, real and inverted. 2F 1 F 1 F 2 2F 2 A B O

### 2) When the image is beyond 2F1, the image is formed between F2 and 2F2, is diminished, real and inverted. :

2) When the image is beyond 2F 1 , the image is formed between F 2 and 2F 2 , is diminished, real and inverted. A B 2F 1 F 1 F 2 2F 2 A’ B’ O

### :

3) When the object is at 2F 1 , the image is formed at 2F 2 , is same size as the object, real and inverted. A B 2F 1 F 1 F 2 2F 2 A’ B’ O

### 4) When the object is between 2F1 and F1, the image is formed beyond 2F2, is enlarged, real and inverted.:

4) When the object is between 2F 1 and F 1 , the image is formed beyond 2F 2 , is enlarged, real and inverted. A B 2F 1 F 1 O F 2 2F 2 A’ B’

### 5) When the object is at F1, the image is formed at infinity, is highly enlarged, real and inverted.:

5) When the object is at F 1 , the image is formed at infinity, is highly enlarged, real and inverted. 2F 1 F 1 O F 2 2F 2 A B

### 6) When the object is between F1 and the optical centre, the image is formed on the same side as the object, is enlarged, virtual and erect.:

6) When the object is between F 1 and the optical centre, the image is formed on the same side as the object, is enlarged, virtual and erect. F 2 2F 2 F 1 2F 1 A B A’ B’ O

### TERMS USED IN THE STUDY OF CONCAVE LENS XY - Principal axis F - Principal focus O - Optical centre OF - Focal length :

TERMS USED IN THE STUDY OF CONCAVE LENS XY - Principal axis F - Principal focus O - Optical centre OF - Focal length F O 2F X Y

### IMAGES FORMED BY CONCAVE LENS 1) When the object is at infinity, the image is formed at the focus F1, is highly diminished, virtual and erect.:

IMAGES FORMED BY CONCAVE LENS 1 ) When the object is at infinity, the image is formed at the focus F 1 , is highly diminished, virtual and erect. 2F 1 F 1 O A B

### 2) When the object is between infinity and the optical centre, the image is formed between the focus F1 and optical centre, is diminished, virtual and erect. :

2) When the object is between infinity and the optical centre, the image is formed between the focus F 1 and optical centre, is diminished, virtual and erect. 2F 1 F 1 F 2 2F 2 A B A’ B’ O

### LENS FORMULA FOR SPHERICAL LENSES:

LENS FORMULA FOR SPHERICAL LENSES The lens formula for spherical lenses is the relationship between the object distance, image distance and focal length. The lens formula is expressed as :- 1 1 1 v u f MAGNIFICATION PRODUCED BY SPHERICAL LENSES With respect to the object size and image size, magnification is the ratio of the size of the image to the size of the object. Height of the image h’ Magnification = m = Height of the object h The magnification is also related to the object distance and image distance. It can be expressed as :- h’ v Magnjfjcation m = = h u