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An object is placed at the focus of concave lens having focal length f. What is the magnification and distance of the image from the optical centre of the lens?

Asked in JEE Main 31st Aug 1st Shift 2021 · Lens formula and magnification

Answer: (2) 1/2, f/2

Step-by-step solution

Concave lens: focal length -f, object at u=-f.

1/v=1/(-f)+1/(-f)=-2/f, v=-f/2

m=v/u=1/2, image f/2 from the optical centre.

Why the other options are wrong

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