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JEE Main 2016 · Optical Instruments & the Eye

Optical Instruments & the Eye question from JEE Main 2016

Q38JEE Main 2016Easy

Optical Instruments & the Eye

An observer looks at a distant tree of height $10\text{ m}$ with a telescope of magnifying power of $20$ To the observer the tree appears:

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Answer: (b)

A telescope makes the visual angle $M$ times larger: $\beta = 20\alpha$ .
The same angle would be seen if the tree were $20$ times closer; its height does not change.
So the answer is (b) 20 times nearer.

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