To investigate the relationship between u and v for a convex lens.

To investigate the relationship between u and v for a convex lens.

Prediction

I predict that the values of u two times greater than the focal length of the lens, the image will be diminished and the value for v will be greater than the focal length of the lens but not greater than two times the focal length of the lens. The bigger u the smaller the image and closer to the focal length v is. A simple ray diagram can prove this:

I also predict that the values of v less than two times the focal length but greater than the focal length the image will be magnified and the value for v will be greater than twice the focal length. The closer to the focal length v is the more magnified the image and the bigger the value of v. This can be proved by this diagram:

I also predict that for the values of u less than f a virtual image will be produced as this does not connect u and v there is no point using values of u less than the focal length.

Ideal Results

My Ideal results are on a separate page and were calculated using the formula

/u+1/v=1/f

u= the distance of the object from the lens

v= the distance of the image from the lens

f= the focal length of the lens

I found this formula in my research

(Internet, http:// relativity.phy.olemiss.edu) and is widely accepted as reliable way of finding the focal length of a lens.

Preliminary Investigations

My first preliminary investigation will be to find out which is the focal length of the lens that gives a good range of results for v. Another use for this preliminary is too see how clear the image is.

For a focal length of 5 centimetres

u

v

0

1.5

00

5.238

The image is very small and there is not a clear image. The image is blurred. The differences are very hard to measure. There is not a wide range of results.

For a focal length of 10 centimetres

u

v

20

20.7

00

0.2

The image is bigger than when the focal length was 5 centimetres but it is still too small. The image is also clearer but is still too blurred. The range is wider but again is not big enough because the differences are hard to measure.

For a focal length of 15 centimetres

u

v

20

70.5

00

29.4

The image is big enough to be easily measured and the image ...