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JAMB Physics 2020 Objective — Question 17

Question 17 of 40 from the Joint Admissions and Matriculation Board (JAMB) Physics 2020 Objective paper, with the correct answer and a full explanation.

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17. The distance between the object and the pinhole of a pinhole camera is reduced by a factor of 4. The size of the imaged

  • A. A. is quadrupledCorrect
  • B. B. is reduced to a quarter
  • C. C. is doubled
  • D. D. remains unchanged

Explanation

Magnification (image size/object size) = image distance/object distance. Since object distance is reduced by a factor of 4, the magnification (and hence image size, for fixed screen/image distance) increases fourfold — the image is quadrupled.

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