Question

19- If the magnification of a mirror is negative, which of the following is correct?

A) The image is upright and the mirror is convex.

B) The image is inverted and the mirror is convex.

C) The image is inverted and the mirror is concave.

D) All of the previous answers can be correct.

E) None of the previous answers is correct.

The correct answer is C ...... can somebody please give me a simple explanation for why this is the case. I thought a negative magnification meant the image is just inverted, how do we automatically know it is concave as well? Please do not use a ton math in your answer just explain it to me

Answer 1

Magnification is defined as

M = -(v/u)

Where v is distance of image from mirror and u is distance of object from mirror.

Now, in the case of cancer mirror, image and object are always on the other sides of the mirror and hence using sign convention u is taken as negative while v is taket as positive. This eventieven results in positive magnification (always).

Therefore a convex mirror always have positive magnification and a negative magnification means mirror is concave.