Though hypermetropia can be corrected by convex lens, why are we putting negative sign for image distance (v) for solving problems? I have learned that image distance is negative for concave mirror and lens and positive for convex mirror and lens.DO ANY ONE HAS A CORRECT EXPLANATION FOR THIS?
Answers
Answer:
This is because of CARTESIAN SIGN CONVECTION.
Explanation:
Accoding to this,
We have to relate our ray diagram with a number line.
1. The optical centre is taken to be the origin.
2. The object us always placed on the left of the lens.
3. All distances parallel to principle axis are measured from the optical center and thise which are on the left are considered to be negative since in numberline, negative numberings are found to the left of the optical centre on x-axis.
Answer: hypermetropia uses convex lens but we use negative sign in solving numerical on hypertropic eye because the The defective near point is taken as the image distance in hypermetropia case. As the defective near point is at the left side of the lens, it is taken as negative.
you can see from the diagram.
