Q122 / 180 · NEET 2018 · Physics

An astronomical refracting telescope will have large angular magnification and high angular resolution, when it has an objective lens of

  • Correct answer
    A
    large focal length and large diameter
  • B
    large focal length and small diameter
  • C
    small focal length and large diameter
  • D
    small focal length and small diameter

Solution

For astronomical refracting telescope

Angular magnification is more for large focal length

Of objective lens M.P=f0fe

Resolving power =D1.22λ

Resolving power is high for large diameter.

So, objective lens should have large focal length (f.) and large diameter D

Hence, the correct answer is option: 'A'.

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