This note provides us with an information about Image formed by lenses .
Some related term to format image is Center of curvature ,radius of curvature ,optical centre ,principle axis ,focal length ,focal plane ,
This note provides us with an information about the power of lens and measurement of focal length .The power of a lens is a measure of its ability to produce the deviation of light. A lens of short focal length produces more deviation of light than that of a lens of larger focal length. So, power of a lens is defined as the reciprocal of its focal length