Q. A terrestrial telescope is made by introducing an erecting lens of focal length $f$ between the objective and eye piece lenses of an astronomical telescope. This causes the length of the telescope tube to increase by an amount equal to
A) $f$
B) $2f$
C) $3f$
D) $4f$
Explanation
The correct answer is Option D: $4f$.
A detailed explanation for this question is being prepared.
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.