A lens is a transparent medium bounded by two surfaces atleast one of which is a curved surface.
Convex lens (Converging lens) is thicker at the centre and narrower at the edges.
It is used in optical instruments such as microscope, telescope etc for magnifying images.
Concave lens (diverging lens) is narrower at the centre and thicker at the edges.
Type of image formed by diverging lens - Small, virtual image
Lens is not used in pinhole camera.
The ability of an optical instrument to produce separate images of two objects clearly is called - Resolving Power
Focal length and power of a concave lens is always negative.
Focal length and power of a convex lens is always positive.
When a convex lens is placed in water is focal length - Increases
Power of a lens increases as its focal length - decreases.
World's fastest radio telescope was constructed by - Australia
The world's largest Radio Telescope - FAST (Five-hundred-meter Aperture Spherical Radio Telescope) (launched in China)
Power is the reciprocal of focal length P=1/f
Persistence of vision of human eye is 1/16 seconds
Speed of Modern movies is 24 frames per seconds.
Short sight can be rectified by using Concave lens
Long sight can be rectified by using Convex lens
Convex lens is also known as Converging lens
Concave lens is also known as Diverging lens
The lens in Human Eye - Convex Lens
Image formed in Convex lens - Real and inverted
Image formed in Concave lens - Virtual and erect
Power of a lens is measured in - Dioptre
Lens used as magnifying glass - Convex Lens
Lens used in Microscope and Telescope - Convex Lens
Short sight and long sight can be corrected together by - Bifocal Lens
Bifocal Lens was invented by Benjamin Franklin
No comments:
Post a Comment