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An observer looks at a distant tree of height 10 m with a telescope of magnifying power of 20. To the observer the tree appears:

1. 10 times taller
2. 10 times nearer
3. 20 times taller
4. 20 times nearer

Correct answer: 20 times nearer

Solution

A telescope's magnifying power describes angular magnification: the object subtends an angle 20x larger, so the tree appears 20 times nearer (not literally 20 times taller). Answer: 20 times nearer.

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