Reading Spectacles Simulation
This 3D simulation demonstrates how reading glasses correct vision by creating a virtual image at the eye's least distance of distinct vision (50 cm) when reading material is held at the normal near point (25 cm).
Optical Calculations
Physics Explanation
For a person with a least distance of distinct vision of 50 cm, reading glasses must form a virtual image at 50 cm when the object (reading material) is at the normal near point (25 cm).
The lens formula relates object distance (u), image distance (v), and focal length (f):
\[ \frac{1}{f} = \frac{1}{v} - \frac{1}{u} \]
With \( u = -25 \) cm and \( v = -50 \) cm (negative for virtual image on same side as object):
\[ \frac{1}{f} = \frac{1}{-50} - \frac{1}{-25} = \frac{1}{50} \]
Thus \( f = +50 \) cm (convex lens) with power \( P = \frac{1}{f} = +2 \) D.
