Question

why we use distance negative in numerical of reflection and refraction​

Answer 1

Answer:

Distances measured on the other side are negative. f, the focal length, is positive for a concave mirror, and negative for a convex mirror. ... When the image distance is negative, the image is behind the mirror, so the image is virtual and upright. A negative m means that the image is inverted.Since, object is always placed in front of the mirror hence the sign of object is taken as negative. Since, the centre of curvature and focus lies behind the convex mirror, so sign of radius of curvature and focal length are taken All distances parallel to the principal axis are measured from the pole of the mirror. All the distances measured to the right of the origin (along + x-axis) are taken as positive while those measured to the left of the origin (along � x-axis) are taken as negative.