Spherical mirror;find focal length from given data?

AI Thread Summary
The discussion centers on finding the focal length of a concave mirror when two objects at distances u1 and u2 produce images of the same size. The relevant equation is 1/v + 1/u = 1/f. Participants clarify that the images formed at u1 and u2 are equal in size, not the objects themselves. There is confusion about whether two points can yield images of the same size, especially as the object distance increases. The conversation emphasizes the need to consider both virtual and real images to solve the problem effectively.
vkash
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Homework Statement



When an object is at distance u1 and u2 from pole of concave mirror, images of same size are formed. Find the focal length of the mirror.

Homework Equations



1/v+1/u=1/f

The Attempt at a Solution



Can u please ray diagram for this question. I think their is only one point from which image of size of object form(that's 2f). But it is giving two points. So how to do it..
 
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I think you're misreading the question. It's not saying the image is the same size as the object. It's saying the image formed when the object is at u1 is the same size as the image formed when the object is at u2.
 
vela said:
I think you're misreading the question. It's not saying the image is the same size as the object. It's saying the image formed when the object is at u1 is the same size as the image formed when the object is at u2.

OK!
acha ji.()

but is it possible that two points have same size of image(for a fixed object). I think it will decrease as we take object from pole of the lens to infinity...

please tell me how to proceed..
 
Think virtual and real images.
 

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