Lens - find the focal length

  • #1
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Lens -- find the focal length

1. An object 3.0 cm tall is placed 20 cm in front of a converging lens. A real image is formed 10 cm from the lens. What is the focal length of the lens?



2. 1/f = 1/do + 1/di



3. 1/f = 1/do + 1/di
1/f = 1/20 + 1/10
f = 6.667 cm

I'm not sure if this is right and if you can can you show me how the diagram would look like. Thank You!!
 

Answers and Replies

  • #4
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Thank You!!
 

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