In order to create a magnifier in convex lens, you should choose a short focal length that is lesser than 1 meter.
A convex lens is also referred to as converging lens and it can be defined as a type of lens that typically causes parallel rays of light with respect to its principal axis to come to a focus (converge) and form a real image.
In Science, a magnifier refer to an optical instrument that allow us to look at a very near object because its image is generally formed farther away. Thus, the image of the object appears to be much larger.
In this context, you should choose a short focal length that is lesser than 1 meter when you want to create a magnifier in convex lens because the nearer the object is to the lens, the larger would be the image formed.
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