magnification of lens is -1, then nature of lens is ___
Answers
Explanation:
The thickness of the lens affects how much it bends light and therefore the power of the lens. This can be measured using the focal length (f) of the lens.
For a convex lens this is the distance from the centre of the lens to the point at which parallel rays of light converge (meet). The shorter the distance the more powerful the lens, the light has been refracted more.
For a concave lens this is the distance from the centre of the lens to a where rays appear to have come from when parallel rays entered the lens.
However is is quite rare that we will be dealing with parallel rays as they are from a distance source. The lenses will will bring the rays of light to a focus at points other than the focal distance. To understand this we need to be able to construct ray diagrams.
To draw a ray diagram, we draw 3 rays front the top of the object:
Horizontally to the axis of the lens and the through the far focal point
Through the centre of the lens which is no refracted ie straight through
Through the near focal point to the axis of the lens and then horizontally out the otherside
Where the rays converge (meet/cross) or appear to have come from converging is were the image is formed.
