passwella.
Menu

JAMB Physics 1994 Question 37

Question 37

Lenses and Optical Instruments

In a projection lantern of focal length f, the object distance u, is such that

  1. A.u > 2f > f
  2. B.u < f < 2f
  3. C.u = f < 2f
  4. D.f < u < 2f
Show the answer and explanation

Answer: D (f < u < 2f)

Explanation

A projector must give a real, magnified image on a distant screen, so the slide is placed between f and 2f from the lens.