In telescopes we use eye-piece which has focal length
Correct answer: B. Very small
- A. Very large
- B. Very small
- C. Variable
- D. Moderate
Explanation
The correct answer is Very small. Telescopes use eye-pieces with very small focal lengths to maximize magnification, allowing observers to see distant objects more clearly. Option A is incorrect because a large focal length results in lower magnification, not suitable for telescopes. Option C is misleading since while some telescopes may offer variability, the primary function relies on small focal lengths. Option D is incorrect because a moderate focal length does not provide the high magnification needed for effective telescopic observation.
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