An object is placed 30 cm from a convex lens of focal length 20 cm. At what distance from the lens is the image formed?
Answer and explanation
Correct answer: C. 60 cm
- Step 1: With and : , so cm. Answer: 60 cm. Why not the others: 12 cm: uses a plus sign in the denominator. 15 cm: assumes the image is halfway. 50 cm: adds the object distance and focal length.
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