Physics Review Question

Unit: Optics
Year: 1990 Question#: 99
Question: An object 0.16 meter tall is placed 0.20 meter in front of a concave (diverging) lens. What is the size of the image that is formed 0.10 meter from the lens?

(1 ) 0.040 m
(2 ) 0.080 m
(3 ) 0.16 m
(4 ) 0.32 m

What is this question really asking?

Explanation by: Kevin E

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Answer 1
0.040 m


Whatever method you used was incorrect. return to top

Answer 2
.0800 m


This is the correct answer. The question gives you 3 variables out of the four necessary for the equation:

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Answer 3
0.16 m


The height of the image does not necessarily equal the height of the object when dealing with curved lenses. return to top

Answer 4
0.32 m


The correct ratio is NOT the distance of the object from the lens, divided by the distance of the image from the lens equals the height of the image divided by the height of the object. This seems to be your mistake. return to top

What's this question really asking?

The question is fairly striaght forward, it tells you that the distance of the object from the lens is .20 m, the distance of the image from the lens is .10 m, the height of the object is .16 m, and you are asked to find the height of the image. return to top

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