A converging lens has focal length 8 cm. An object is placed 24 cm from it. At what distance is the image formed?

Answer and explanation

Correct answer: A. 12 cm

  1. Step 1: Use the lens equation 1/f = 1/u + 1/v, so 1/v = 1/f - 1/u.
  2. Step 2: 1/v = 1/8 - 1/24, giving v = 12 cm.
Answer
12 cm.
Why not the others: '32 cm' adds the object distance and the focal length; '16 cm' subtracts the focal length from the object distance; '192 cm' multiplies instead of using the reciprocal formula.

Practise more Mechanics, Heat, Electricity, Waves and Optics.

Free questions with an explanation for every one, and full timed Državna Matura (Bosnia & Herzegovina) mock tests.