Image Formation by Lens

Formation of Images by Lenses

7.1

Formation of Images by Lenses

Lens

Lens is a transparent medium such as glass which has one or two curved surfaces

Lens

Convex and concave lens

Convex lens = converging lens:

biconvex
planoconvex
convex meniscus

Concave lens = diverging lens:

binconcave
planoconcave
concave meniscus

Determining the focal length of convex and concave lens

Position and characteristics of images formed by a convex lens

Position of object	Position of image	Characteristic of image
Object is further than 2F	Image is between F and 2F	Real Inverted Diminised
Object is at 2F	Image is at 2F	Real Inverted Same size as object
Object is between F and 2F	Image is further than 2F	Real Inverted Magnified
Object is at F	Image is at infinity	Virtual Upright Magnified
Object is between F and optical centre	Image distance is further than F	Virtual Upright Magnified

Position and characteristics of images formed by a concave lens

Position of object	Position of image	Characteristic of image
Object is further than 2F	Between optical centre and focal point	Virtual Upright Diminished
Object is between F and optical centre	Between optical centre and focal point	Virtual Upright Diminished

Formation of Images by Lenses

7.1

Formation of Images by Lenses

Lens

Lens is a transparent medium such as glass which has one or two curved surfaces

Lens

Convex and concave lens

Convex lens = converging lens:

biconvex
planoconvex
convex meniscus

Concave lens = diverging lens:

binconcave
planoconcave
concave meniscus

Determining the focal length of convex and concave lens

Position and characteristics of images formed by a convex lens

Position of object	Position of image	Characteristic of image
Object is further than 2F	Image is between F and 2F	Real Inverted Diminised
Object is at 2F	Image is at 2F	Real Inverted Same size as object
Object is between F and 2F	Image is further than 2F	Real Inverted Magnified
Object is at F	Image is at infinity	Virtual Upright Magnified
Object is between F and optical centre	Image distance is further than F	Virtual Upright Magnified

Position and characteristics of images formed by a concave lens

Position of object	Position of image	Characteristic of image
Object is further than 2F	Between optical centre and focal point	Virtual Upright Diminished
Object is between F and optical centre	Between optical centre and focal point	Virtual Upright Diminished