What is the eye ring of a telescope or microscope ?

Limit of resolution of a telescope and microscope imposing because of which ?

The focal length of the objective of an astronomical telescope is 1.0 m. If the magnifying power of telescope is 20, then what is the length of the telescope for relaxed eye ?

In a simple microscope, the lens is held at a distance d from the eye and the image is formed at the least distance d of the distinct vision from the eye. What is the magnifying Power of the microscope ? Where f is the focal length of the lens.

If in compound microscope m_1 and m_2 be the linear magnification of the objective lens and eye lens respectively, then what is the magnifying power of the microscope ?

Can a microscope function as a telescope by inverting it. Can a telescope function as a microscope ?

Focal length of objective and eye piece of telescope are 200 cm and 4 cm respectively. What is the length of telescope for normal adjustment?

Focal length of objective and eye piece of telescope are 200 cm and 4 cm respectively. What is the length of telescope for normal adjustment?

A telescope has an objective of focal length 100 cm and an eye-piece of focal length 5 cm. What is the magnifying power of the telescope when it is in normal adjustment?