In Fizeau method of measuring the speed of light, the toothed wheel is placed in the focal plane of a converging lens. How would the experiment be affected if the wheel is slightly away from the focal plane?

In Fizeau method of measuring the speed of light if the toothed wheel is placed away from the focal length of a converging lens the returning light will fall on an extended surface area of the wheel. In such a case the image will appear even the passage of the light is blocked by one of the teeth of the wheel.


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