NECO 2000 Physics · Question 29

The image formed by a converging lens of focal length is of a distance of 2f from the lens. Calculate the lateral magnification produced

Options

A.0.5
B.1
C.1.5
D.2
E.3

Answer: B. 1

Explanation written with AI and checked against the answer key

Analyze the question: A converging lens has focal length f. The image forms at a distance v = 2f from the lens. We need the lateral (linear) magnification. Concept: The lens formula (real-is-positive convention): 1/f = 1/u + 1/v Magnification: m = v/u (magnitude) Solution: Given v = 2f: 1/u = 1/f − 1/v = 1/f − 1/(2f) = 1/(2f) So u = 2f. Magnification: m = v/u = 2f / 2f = 1 The image is real, inverted, and the same size as the object (magnitude 1). With the sign convention, m = −1, but the magnitude is 1, which is what the options show. Answer: The lateral magnification is 1, which is option B. Tip: When an object is placed at 2f (the center of curvature) of a converging lens, the image is also at 2f, real, inverted, and the same size as the object. So if you see "image at 2f", think magnification = 1 immediately.

AI can make mistakes. Report anything that looks wrong.