Question

In normal adjustment, for a refracting telescope, the distance between objective and eye piece is $30\,cm$ The focal length of the objective, when the angular magnification of the telescope is 2, will be:

• A. $20\, cm$
• B. $30 \,cm$
• C. $10\, cm$
• D. $15 \,cm$

Answer 1

Answer: (A)

$20\, cm$

Answer 2

From the given options the correct answer is option (A): $20\, cm$