Question

Consider that a double convex lens is used as a magnifying glass and the object placed between the optical centre and the focus of the lens. The erect, virtual and magnified image of the object is formed on the same side. The focal length of this lens is 8 cm. If the observer's the eye is kept at a distance of 4 cm from the lens, then the distance between lens and object is equal to the least distance of distinct vision. What is the magnifying power of this lens?
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Answer 1

Answer:

In actuality, there are two focal points for every lens, the same distance from the lens, on opposite sides. The distance from the lens to the focal point is called the focal length. For converging lenses, the focal length is always positive, while diverging lenses always have negative focal lengths.