A converging lens of focal length 10cm forms an erect image three times the size of the real object. Calculate the distance between the image and the object.

  • A 6.6cm
  • B 11.1cm
  • C 13.3cm
  • D 20.0cm
waec 2017physics

The correct answer is C. 13.3cm

Given, image size = 3U

object size = U

focal length = 10cm

lens to object distance = \(\frac{focal length \times object size}{image size}\)

= \(\frac{10 \times u}{3u} = 3.33\)

distance between image and object = 10 + 3.33 = 13.33cm

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