Graphing conves lense relationships to find focal lenght with slope

In summary, the relationship between the object-lens distance and image-lens distance for a converging lens can be represented by the lens equation (1/u)/(1/f) + (1/v)/(1/f) = 1, where u is the object-lens distance, v is the image-lens distance, and f is the focal length. This can also be written in the form of a straight line graph with a slope of -1 and an intercept of 1/f on both the x and y axis.
  • #1
pices_zodiac
1
0

Homework Statement


I need to find the relationship between object-lens distance and image-lens distance for a lense(converging) but cannot graph the relationship in a way that the focal length is the slope for the graph



Homework Equations


1/u + 1/v = 1/f
where u= object lense distance and v= image lense distance and f= focal lenght

y=mx+b --> I would like m=focal length and b=0


The Attempt at a Solution


so far, I can only come up with:
-u ( 1/[uv]) = -1/v
thus ( 1/[uv]) is the slope.. but f= (v+u)/(uv)
 
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  • #2
You can write the lens equation as
(1/u)/(1/f) + (1/v)/(1/f) = 1.
It is in the form of
x/a + y/b = 1.

Draw the graph 1/u vs 1/v. You will get a straight line with slope (-1). The intercept on x and y-axis are equal and it is equal to 1/f.
 
  • #3
which is not the slope

I would suggest approaching this problem by first understanding the concept of focal length and its relationship to object-lens distance and image-lens distance. Focal length is defined as the distance between the center of a lens and its focal point, where parallel rays of light converge to a single point. This distance is constant for a given lens and is a key factor in determining the magnification and clarity of an image.

To graph the relationship between object-lens distance and image-lens distance, you can plot the values for u (object-lens distance) on the x-axis and v (image-lens distance) on the y-axis. The resulting graph should show a linear relationship between the two variables. However, the slope of this line will not directly represent the focal length.

To find the focal length using the graph, you can use the equation 1/u + 1/v = 1/f. Rearranging this equation to solve for f, you get f = uv/(u+v). This means that the value of f can be determined by finding the product of u and v, and then dividing it by the sum of u and v. This calculation can be done for any point on the graph, and the resulting value will represent the focal length for that specific object-lens and image-lens distance.

In terms of your desired equation of y=mx+b, it is important to note that in this case, the slope (m) would not represent the focal length, but rather the inverse of the focal length (1/f). This is because as u increases, v decreases, and vice versa, resulting in a negative slope. However, the y-intercept (b) would still be 0, as it represents the point where the line intersects the y-axis when u=0.

In conclusion, while the slope of the graph does not directly represent the focal length, it can still be used to determine the focal length using the equation 1/u + 1/v = 1/f. I hope this explanation helps you better understand the relationship between object-lens distance, image-lens distance, and focal length.
 

1. What is the purpose of graphing convex lens relationships?

The purpose of graphing convex lens relationships is to determine the focal length of the lens. This information is useful for understanding the properties of the lens and how it affects the behavior of light passing through it.

2. How is the focal length of a convex lens measured?

The focal length of a convex lens is typically measured by determining the distance between the lens and the point where the light rays converge. This can be done using a variety of methods, including graphing the relationship between object distance and image distance.

3. What is the relationship between the slope of a graph and the focal length of a convex lens?

The slope of a graph depicting the relationship between object distance and image distance for a convex lens is equal to the inverse of the focal length. This means that the steeper the slope, the shorter the focal length, and vice versa.

4. Can the focal length of a convex lens be negative?

Yes, the focal length of a convex lens can be negative. This occurs when the lens is unable to form a real image, and instead, the light rays converge to form a virtual image. The sign convention for focal length dictates that a negative value indicates a virtual image.

5. How does the curvature of a convex lens affect its focal length?

The curvature of a convex lens directly affects its focal length. A lens with a greater curvature (i.e. more bulging) will have a shorter focal length, while a lens with less curvature will have a longer focal length. This relationship is demonstrated by the curvature of the lens being a factor in the equation for calculating focal length.

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