Notes from the JEE Toppers
2 : Lens Formula and Magnification
- The lens formula is $$(\frac{1}{f} = \frac{1}{v} - \frac{1}{u}),$$ where (f) is the focal length, (v) is the image distance, and (u) is the object distance.
- Positive values for (v) and (u) indicate real images, while negative values indicate virtual images.
- Magnification ((M)) is given by $$(M = \frac{h_i}{h_o} = -\frac{v}{u}).$$ The negative sign indicates inversion.
- Lenses follow the sign conventions: converging lenses have positive focal lengths, while diverging lenses have negative focal lengths.
