Quiz : Optical Instruments

The light emitted from a light-emitting diode (LED) has a wavelength.

Which of the phenomena of light is used in the propagation of light through optical fibers?

In the newer systems of fiber optics, signals are regenerated by placing repeaters which may be separated by as much as ____ km.

The minimum distance from the eye at which an object appears to be distinct is ____ cm.

Which combination can ensure less diffraction and more details to be seen by compound microscope?

If a single convex lens is placed close to the eye, then it is being used as ____.

The image formed by a simple microscope is ____.

The optical fiber is covered for protection by a_______.

If the magnifying power of magnifying glass is 3, then the focal length will be _____.

The distance of near point from the eye is about:

The information carrying capacity of optical fiber is called:

A converging lens of focal length "f" is used as a magnifying glass. What is its angular magnification?

An astronomical telescope having magnifying power of 5 consists of two thin lenses 24 cm apart. The focal length of objective lense is__________.

In a multimode step-index fibre, the density of the optical material decreases from ___.

The speed of sound is independent of ___________.

When light enters from water into the air, its speed_______.

Glass-air boundary acts as a/an_______.

Nowadays, a new type of optical fibre is being used in which the central core has a high refractive index and its density gradually decreases towards its periphery. This type of optical fibre is called: