# physics, lenses

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I need to calculate the magnification, m of an objective lens, so I can then x it by the eyepiece value for M to get the total magnification.

I need v/u (v is dist from lens to image; u is dist of object to lens)

I'm using 1/f = 1/v+1/u rearranged for 1/v.

That's: 1/v = 1/f - 1/u. I think?

The object is 26mm away from the lens; the focal length is 25mm.

I keep getting v = 500mm! (650mm too).

Any ideas where i'm going wrong please?

Thanks.

• physics, lenses -

it depends on the position of the object. u need to c that if v and u bth are on same side or opposite side because that changes the sign of v and u to positiv and negative. i hope u gt tht

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