What kind of lens is behind the orange curtain?

Horizontal position of the object
-200 cm -25 cm
Check here to show multiple rays
Select the type of lens and use the slider to set the magnitude
of the focal length, and then check your answer
Type of lens: Converging lens Diverging lens
Magnitude of the focal length
30 cm 100 cm

Inspired by a 2002 article in The Physics Teacher by Melissa Dancy, Wolfgang Christian, and Mario Belloni.

Test your familiarity with lenses. You can find the focal length of a converging or diverging lens by calculating it, but see if you can get to the point where you can find it without doing a calculation.

Simulation first posted on 3-10-2018. Written by Andrew Duffy

Creative Commons License
This work by Andrew Duffy is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License.
This simulation can be found in the collection at http://physics.bu.edu/~duffy/classroom.html.

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