JAMB Physics 2008 Objective — Question 34
Question 34 of 50 from the Joint Admissions and Matriculation Board (JAMB) Physics 2008 Objective paper, with the correct answer and a full explanation.
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34. If a convex lens of focal length 12cm is required to produce a real image four times the size of the object, how far from the lens must the object be placed?
- A. 10cm
- B. 15cmCorrect
- C. 20cm
- D. 25cm
Explanation
With magnification m=4: 1/f = 1/u + 1/v and v=4u give 1/12 = 5/(4u), so u = 15cm.
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