An object is 20 cm from a converging lens of focal length 15 cm. How far from the lens is the image formed?
Answer and explanation
Correct answer: A. 60 cm
- Step 1: Lens equation , so .
- Step 2: cm.
Answer
60 cm.
Why not the others: 8.571 cm: a sign was wrong in the lens equation. 5 cm: the focal length was subtracted from the object distance. 35 cm: the focal length was added to the object distance.
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