# Mirror question

#### Jodi

Hi; Could someone please help me with the following question: The image of a distant tree is virtual and very small when viewed in a curved mirror. The image appears to be 18.8 cm behind the mirror. What is its radius of curvature? (Use positive for concave and negative for convex). Would I use the mirror equation 1/do + 1/di = 1/f? How would I go about this question? Thanks

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#### OlderDan

Homework Helper
Jodi said:
Hi; Could someone please help me with the following question: The image of a distant tree is virtual and very small when viewed in a curved mirror. The image appears to be 18.8 cm behind the mirror. What is its radius of curvature? (Use positive for concave and negative for convex). Would I use the mirror equation 1/do + 1/di = 1/f? How would I go about this question? Thanks
Your equation will get you started. The object distance can be taken as infinite. Solve the equation for the focal length. Radius of curvature is related to the focal length. Do you know how?

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