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JAMB Physics 2012 Question 31

Question 31

Light and Reflection

A pinhole camera is placed 300m in front of a building so that the image is formed on a screen 5cm from the pinhole. If the image is 2.5cm high, the height of the building will be

  1. A.25m
  2. B.50m
  3. C.100m
  4. D.150m.
Show the answer and explanation

Answer: D (150m.)

Explanation

Object height ÷ image height = object distance ÷ image distance = 300 m ÷ 0.05 m = 6000. Building height = 0.025 m × 6000 = 150 m.