Focal Length: Definition, Equation & Examples


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question 1 of 3

The focal length of a convex lens _____.

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1. What is the focal length of the lens in the following drawing?

2. What is the optical power of a lens with a focal length of 2.5 cm (0.025 m)?

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About This Quiz & Worksheet

Assess your understanding of focal length by completing this quiz and worksheet. To pass, you must be familiar with the focal-length equation, characteristics of lenses and optical power.

Quiz & Worksheet Goals

You will be tested on:

  • Finding the optical power of a given lens
  • A convex lens' focal length
  • Characteristics of convex lenses

Skills Practiced

  • Knowledge application - use your knowledge to identify the focal length of a depicted lens
  • Reading comprehension - ensure that you draw the most important information from the lesson on focal length
  • Distinguishing differences - compare and contrast topics from the lesson such as concave and convex lenses

Additional Learning

Learn more about lenses by completing the lesson titled Focal Length: Definition, Equation & Examples. Objectives covered include:

  • Define focal length
  • Review a schematic of convex and concave lenses
  • Know the focal-length equation