An astronomical telescope in normal adjustment has an objective of focal length and an eyepiece of focal length . What are its magnifying power and the separation between the lenses?
Answer and explanation
Correct answer: C. and
- Step 1: In normal adjustment (final image at infinity), magnifying power is .
- Step 2: Length of the telescope tube is .
Answer
and .
Why not the others: subtracts focal lengths; multiplies focal lengths; and uses an incorrect eyepiece ratio.
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