Sign Convention: Mirror Image Height
In optics, a standard sign convention is used to define distances and heights related to mirrors and lenses.
- Heights measured upwards from the principal axis are considered positive.
- Heights measured downwards from the principal axis are considered negative.
An erect image is an image that has the same orientation as the object. If we assume the object itself is placed upright (having a positive height), an erect image will also be oriented upwards relative to the principal axis.
Therefore, according to the sign convention, the height of an erect image is always measured upwards from the principal axis.
Conclusion: The height of an erect image formed by a mirror is taken as Positive.
Important Questions from Refraction and Reflection
- How can you identify a concave and a convex mirror based on the direction of their reflecting surfaces?
- Stars appear to twinkle in the night sky because ______.
What type of image is always formed by a concave lens, no matter where the object is placed?
- Which of the following is NOT caused by atmospheric refraction?
In the case of a convex mirror, a ray parallel to the principal axis after reflection appears to diverge from:
