Question

Choose the correct statement/s with respect to the lenses of a Refracting telescope.

• A. The objective lens has large diamater and larger focal length.
• B. The objective lens has large diamater but smaller focal length.
• C. The eyepiece has small diameter and smaller focal length.
• D. The eyepiece has small diameter but larger focal length.

Answer 1

Answer: (A), (C)

The correct options are
A The objective lens has large diamater and larger focal length.
C The eyepiece has small diameter and smaller focal length.

In a Refracting telescope, the objective lens has large diameter and larger focal length because of which maximum amount of light coming from the distant object can be collected.
On the other hand the size of the eyepiece is small and its
focal length is also smaller. Both the lenses are fitted inside a metallic tube in such a way that the distance between them can be changed. The principal axes of both the lenses are along the same straight line.
Generally, using the same objective but different eye pieces, different magnification can be obtained.