A real object is placed at a distance from the optical center of a convex lens of focal length . If the linear magnification is (real, inverted image of double size), what is the object distance in terms of ?

Answer and explanation

Correct answer: B.

  1. Step 1: For a lens, linear magnification is . Here .
  2. Step 2: Use the lens formula: .
  3. Step 3: Combine fractions: .
Answer
.
Why not the others: gives magnification ; gives a virtual erect image (); gives unit magnification ().

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