Optics, calculating image distance,.given magnification and focal length

AI Thread Summary
To calculate the object and image distances for a converging lens with a focal length of 20 cm and an upright image three times the size of the object, the lens equation and magnification formula must be applied correctly. The lens equation is 1/object + 1/image = 1/20, while the magnification formula states that magnification (M) equals the object distance (ob) divided by the image distance (im). The magnification of 3 indicates that the object distance is one-third of the image distance. Clarification is needed on whether the image is real or virtual, as this affects the calculations. Accurate application of these formulas will lead to the correct solution.
faria123
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Homework Statement


The image obtained with a converging lens is upright and 3x the length of the object. The focal length of the lens is 20cm. Calculate the object and image distances


Homework Equations



I have absolutely no idea how to even start this question

The Attempt at a Solution


1/object + 1/image = 1/focal (lens equation )
1/ob + 1/im= 1/20

M = ob/im ( magnification formula)
3= ob/im

I tried solving for each variable but it wasnt working...
 
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faria123 said:

Homework Statement


The image obtained with a converging lens is upright and 3x the length of the object. The focal length of the lens is 20cm. Calculate the object and image distances


Homework Equations



I have absolutely no idea how to even start this question

The Attempt at a Solution


1/object + 1/image = 1/focal (lens equation )
1/ob + 1/im= 1/20

M = ob/im ( magnification formula)
3= ob/im

I tried solving for each variable but it wasnt working...

Hi Faria, welcome to PF.

The magnification formula is wrong, look it after. And then show your work in detail.

Is the image real or virtual if the image is upright?

ehild
 

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