10/4/2012
In this Exploration we observe some other characteristics of a converging lens when the object is placed on one side of the lens and the real, inverted image is placed on the other side of the lens.Also, we develop a mathematical relationship between the object distance and the image distance.
The equipment we need: lamp, converging lens, lens holder, paper, meter and meter stick.
First, we measured the focal length under the sun. When the image on the ground is a bright dot, then measure the distance from the dot to the middle of lens by ruler. f=4.5+/-0.2cm
Then we set up the equipment.Measure the height of the object.
And make the object distance to 1.5f, 2f, 3f, 4f, 5f. The place a paper on the other side so that can get a clear image. Then measure the image height. And the object distance and image distance.
Of course, we also reserve the lens in the same object distance. But we got the same image distance. And we also cover the top half of the lens by a paper. It is dimmer as you can see.
Then collect all data and make a form.
Change the object distance to 0.5f There is no image on the paper but we look through the lens at the object to view the image. The image is virtual and repeating.
Set up a graph for those datas.
The y-axis is inverse image distance and the x-axis is negative inverse object distance.The slope is 1.0233 and the y-intercept is 0.218
The y-intercept should be the image distance when x close to zero which means object distance is infinity. The inverse of y-intercept is the focal length of lens which is 4.587. It is closer to what we measured.(4.5+/-0.2) 1/di=1/do(1.0233)+0.2180
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