Question

Is the given assertion correct, the magnification of a convex mirror is always positive but that of a concave mirror may be both positive or negative?

Answer 1

Magnification

1. It's a technique for enlarging an object's apparent size but not its physical size. The term "magnification" is used to describe this enlargement. The term minification or de-magnification refers to a reduction in size when this number is less than one.

Concave and convex mirror

1. A convex mirror has a curved reflective surface that bulges out towards the light source. It's also known as a diverging mirror because it can't focus light.
2. Virtual, reduced, and upright pictures are always formed by convex mirrors.
3. The reflective surface of a concave mirror, on the other hand, is bent inwards away from the light source. Because it reflects light inward to a single focal point, it's also known as a converging mirror.
4. Real and inverted pictures, as well as virtual and erect images, are created by concave mirrors.

Sign of magnification

1. The sign of the magnification is indicative of the orientation of the image.
2. According to the new cartesian sign convention, convex mirrors, which always form upright images have a positive magnification whereas concave mirrors that form both erect and inverted images may have positive or negative magnification respectively.
3. However, one can use a different sign convention as well, but it should be well defined and the inferences should be consistent with the definition.

Therefore, the magnification of a convex mirror is always positive, but that of a concave mirror may be both positive and negative.