Focal Length of Lens: Object 5 cm Tall, 10 cm Away

In summary, the conversation discusses the use of the lens equation and making a sketch to determine the focal length of a convex lens when the resulting image is a fraction of the original object's size. The person is unsure of where to start and what equations to use for this type of problem.
  • #1
dev-hud
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0
An object 5 cm tall is 10 cm from a convace lens. The resulting image is one fifth as large as the object. What is the focal length of the lens?

I have been doing questions involving focal lenght, but not when the resulting image is a fraction of the original image. i do not know where to start or what equation(s) to use?? :(
 
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  • #2
dev-hud said:
An object 5 cm tall is 10 cm from a convace lens. The resulting image is one fifth as large as the object. What is the focal length of the lens?

I have been doing questions involving focal lenght, but not when the resulting image is a fraction of the original image. i do not know where to start or what equation(s) to use?? :(

Use the lens equation. Can you show us what that is? And make a sketch. Could you show us a sketch of the situation?
 

1. What is focal length of a lens?

The focal length of a lens is the distance between the lens and the point where the light rays converge to form a sharp image. It is typically measured in millimeters (mm).

2. How is the focal length of a lens determined?

The focal length of a lens is determined by the curvature of the lens and the refractive index of the material it is made of. It can also be calculated using the thin lens equation, which takes into account the distance of the object and the image from the lens.

3. How does the focal length affect the image produced by a lens?

A shorter focal length results in a wider field of view and a larger image, while a longer focal length produces a narrower field of view and a smaller image. Additionally, a shorter focal length creates a more distorted image, while a longer focal length creates a more magnified, flattened image.

4. What does the object height and distance have to do with the focal length of a lens?

The object height and distance from the lens are important factors in determining the focal length of a lens. These variables are used in the thin lens equation to calculate the focal length. Additionally, the object height and distance can also affect the magnification and field of view of the image produced by the lens.

5. How does the focal length affect the depth of field in a photograph?

The focal length of a lens can affect the depth of field in a photograph. A shorter focal length results in a wider depth of field, meaning more of the image will be in focus. A longer focal length creates a narrower depth of field, resulting in a smaller area of the image being in focus.

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