Question

The astronomical telescope consists of objective and eyepiece. The focal length of the objective is
(a) equal to that of the eyepiece.
(b) shorter than that of eyepiece.
(c) greater than that of eyepiece.
(d) five times shorter than that of eyepiece.

Answer 1

The astronomical telescope consists of objective and eyepiece. The focal length of the objective is  c) greater than that of an eyepiece.

• The objective and eye piece in an astronomical telescope are described with a relationship as fo >fe.
• The magnifying power of the telescope is fo/fe.
• This power becomes large when fo >fe. Thus, the focal length of the objective is greater than the eyepiece.

Answer 2

Explanation:

c) greater than that of eyepiece.