Formula for Magnification of a Lens
The magnification formula for a lens is given by the equation:

magnification (m) = - (image distance) / (object distance)
Explanation
- Image Distance: The distance between the lens and the image formed by the lens.
- Object Distance: The distance between the lens and the object placed in front of it.
- Magnification: It is a measure of how much larger or smaller an image appears compared to the object.
When the magnification value is positive, it indicates that the image is upright. On the other hand, a negative magnification value signifies that the image is inverted.
Sign Convention
- The object distance is taken as positive for objects placed on the same side as the incident light and negative for objects on the opposite side.
- The image distance is taken as positive for real images and negative for virtual images.
Applications
The magnification formula is crucial in various optical instruments such as microscopes, telescopes, and cameras. It helps in determining the size and clarity of the images produced by these devices. Understanding the magnification of a lens is essential for achieving desired results in imaging and observation tasks.
By applying the magnification formula, one can calculate the magnification factor of a lens and adjust the object and image distances to obtain the desired magnification level. This formula plays a significant role in the field of optics and is fundamental in the study of light and vision.