Ray Optics: Refraction and Lenses

Refraction and Lenses: Audio Guided Solution

Problem 20:

The converging lens on Julia's camera has a focal length of 52 mm. She uses the camera to take a picture of her friends at South's homecoming. Her friends are located a distance of 2.45 m from the camera as Julia focuses in on them. Calculate the distance from the lens to the film (i.e, the image distance).

Audio Guided Solution

Habits of an Effective Problem Solver

  • Read the problem carefully and develop a mental picture of the physical situation. If necessary, sketch a simple diagram of the physical situation to help you visualize it.
  • Identify the known and unknown quantities and record them in an organized manner. Equate given values to the symbols used to represent the corresponding quantity - e.g., do = 24,8 cm; di = 16.7 cm; f = ???.
  • Use physics formulas and conceptual reasoning to plot a strategy for solving for the unknown quantity.
  • Identify the appropriate formula(s) to use.
  • Perform substitutions and algebraic manipulations in order to solve for the unknown quantity.

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Get more information on the topic of Refraction and Lenses at The Physics Classroom Tutorial.

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