Refractive index, Physics

Assignment Help:

Refractive index:

The most important optical measurement for any transparent material is its refractive index (n). The refractive index is the ratio of the speed of light (c) in a vacuum to the speed of light in the medium:

The speed of light in a material is always slower than in a vacuum, so the refractive index is always greater than one in the optical part of the spectrum. Although light travels in straight lines through optical materials, something different happens at the surface. Light is bent as it passes through a surface where the refractive index changes. The amount of bending depends on the refractive indexes of the two materials and the angle at which the light strikes the surface between them.

The angle of incidence and refraction are measured not from the plane of the surfaces but from a line perpendicular to the surfaces. The relationship is known as "Snells Law", which is written; ni sin I = nr sin R, where ni and nr are the refractive indexes of the initial medium and the medium into which the light is refracted. I and R are the angles of incidence and refraction.

1747_REFRACTIVE INDEX.png

Snell's law indicates that refraction can't take place when the angle of incidence is too large. If the angle of incidence exceeds a critical angle, where the sine of the angle of refraction would equal one, light cannot get out of the medium. Instead the light undergoes total internal reflection and bounces back into the medium.

Figure  illustrates the law that the angle of incidence equals the angle of reflection. It is this phenomenon of total internal reflection that keeps light confined within a fibre optic.

23_REFRACTIVE INDEX1.png


Related Discussions:- Refractive index

Explain the working of transformers, Explain the working of Transformers ...

Explain the working of Transformers A transformer often uses a core, which looks like a square donut of iron, to change the voltage applied to the primary coil to a new larger

B-h curve, BH curve: For any ferromagnetic material there is a definite...

BH curve: For any ferromagnetic material there is a definite value of flux density (B), corresponding to a specified value of magnetising force (H).  These values can be ascert

Angular frequency of the resulting shm, A sphere of mass m and radius r is ...

A sphere of mass m and radius r is on a smooth fixed inclined plane in equilibrium, if now the sphere is displaced by a small distance along the plane , what will be angular freque

Evaluate the refractive index of the liquid, In a Newton's ring experiment ...

In a Newton's ring experiment the diameter of n th ring is 0.46 cm it got shrink to a diameter of 0.40 cm when a liquid is given between the plane glass plate and Plano convex len

The area of a plate assuming a two-plate construction, A capacitor is to be...

A capacitor is to be constructed so that its capacitance is 0.2µF and to take a p.d. of 1.25kV across its terminals. The dielectric is to be mica which, after allowing a safet

Kinematics, A CAR MOVING AT 25m/s ALONG A STRAIGHT LEVEL ROAD EXPERIENCE A ...

A CAR MOVING AT 25m/s ALONG A STRAIGHT LEVEL ROAD EXPERIENCE A RESISTANCE WHICH PRODUCES A RETARDATION OF 0.0001 V^3,WHERE V IS THE VELOCITY IN m/s.FIND THE DISTANCE TRAVELLED AND

Quantum physics, find the kinetic energy of a proton whose debroglie is 1fm...

find the kinetic energy of a proton whose debroglie is 1fm

Evaluate the minimum value of h in terms of r, A sled slides down a frictio...

A sled slides down a frictionless track and loops the loop without falling off. What is the minimum value of h  in terms of  r ? The only other information given is that the an

Light coupling, Light coupling: Another way to look at light guiding in...

Light coupling: Another way to look at light guiding in a fibre is to measure the fibre's acceptance angle. This angle is the angle within which the light should enter the fib

How to find out neutral point, How to find out neutral point ? What all thi...

How to find out neutral point ? What all things we require to equate or form a equation to find the neutral poind and how to do it?

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd