Optical Instruments

The eyepiece of the microscope is bigger than its objective lens.

When an object is placed at a distance of $60cm$ From a convex mirror, the linear magnification produced is $\raisebox{1ex}{$1$}\!\left/ \!\raisebox{-1ex}{$2$}\right.$. Where should the object be placed to obtain a magnification of $\raisebox{1ex}{$1$}\!\left/ \!\raisebox{-1ex}{$3$}\right.$ ?

What are the eyepieces of the microscope called _____?

Is a microscope eyepiece always 10x?

Is Cassegrain telescope or astronomical telescope are same.

A Cassegrain telescope uses two mirrors as shown in the figure. Such a telescope is built with the mirrors $20 \mathrm{mm}$ apart. If the radius of curvature of the large mirror is $220 \mathrm{mm}$ and the small mirror is $140 \mathrm{mm},$ where will the final image of an object at infinity in $\mathrm{mm}$ be?

What is a cassegrain telescope?

Total magnification of compound microscope is $20$ while magnification for eye piece is $5$. If final image is formed at near point which is taken $20 \mathrm{cm}$ then focal length of eye piece is

The focal length of magnifying glass is $25 \mathrm{cm}$ then magnifying power this instrument when image is formed at infinity is ( near point for normal eye$=\mathrm{D}=25 \mathrm{cm}$)

An object is at distance $30 \mathrm{cm}$ from compound microscope of focal length $5 \mathrm{cm}$ and $25 \mathrm{cm}$ for objective and eye piece respectively. Magnifying power of microscope when image is formed at near point is 

Why eyepiece of a telescope is of short focal length while objective is of large focal length ?

A small laboratory telescope has an objective lens of focal, length $140 cm$ and an eye-piece of focal length $6 cm$. Then, separation between the objective and eye-piece is _____.

The focal length of an objective of a telescope is 3 meter and diameter 15 cm. Assuming for a normal eye, the diameter of the pupil is 3 mm for its complete use, the focal length of eye piece must be

 A telescope that uses two converging lenses is called refracting telescope.

 A telescope that uses two converging lenses is called _____ telescope.

An astronomical refracting telescope will have large angular magnification and high resolution, when it has an objective lens of

A giant refracting telescope at an observatory has an objective lens of focal length $15 \mathrm{m}$. If an eyepiece of focal length $1.0 \mathrm{cm}$ is used, what is the angular magnification of the telescope?

In a telescope, the light rays after reflection from the concave mirror are reflected back towards it by a small convex mirror. What type of telescope is this?

A telescope is made up of a concave and plane mirror. Before the reflected rays converge at the focus of the concave mirror, it is again reflected by the plane mirror. What type of telescope is this?

Galileo's telescope consists of four lenses located at the ends of a long tube.