An object is 2.3 cm tall, and 5.5 cm from a converging lens. The image is upright and 9.0 cm tall. What is the focal length of the lens?
1 Answer | Add Yours
The object is 2.3 cm tall, and 5.5 cm from a converging lens. The image is upright and 9.0 cm tall.
The magnification due to the lens is `M = -9/2.3` . In terms of the distance of the object from the lens d, and the focal length f, the magnification is given by `M = f/(f - d)`
Using the values given in the problem and the magnification that has been derived:
`-9/2.3 = f/(f - 5.5)`
=> `-9f + 49.5 = 2.3f`
=> `11.3f = 49.5`
=> `f ~~ 4.38`
The focal length of the lens is approximately 4.38 cm.
Join to answer this question
Join a community of thousands of dedicated teachers and students.Join eNotes