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

Wavelength of the wave , A standing wave is described by the wave function ...

A standing wave is described by the wave function  where x and y are in meters and t is in seconds. (a) Prepare graphs showing y as a function of x for five instants: t = 0, 5 ms,

Can illuminators be computer controlled, Can illuminators be computer contr...

Can illuminators be computer controlled? Practically all can be computer controlled as well as illuminators are not an exception. Color discs, mechanical shutters and lamp volt

What do you understand by absorption coefficient, What do you understand by...

What do you understand by "Absorption coefficient"? which is a better absorber of sound, glass or fibre glass?

Newtons laws concept, tiger woods can hit a golf ball with 55n of force how...

tiger woods can hit a golf ball with 55n of force how hard does the ball hit back on the club

How high will it go, How High Will It Go? The motion of the sledder wit...

How High Will It Go? The motion of the sledder within the animation below is same to the motion of a roller coaster car on a roller coaster track. The similarity of the two mot

Pressure, The input piston of a hydraulic jack has cross sectiona

The input piston of a hydraulic jack has cross sectiona

Modulus of elasticity, (a). Modulus of elasticity and modulus of rigidity a...

(a). Modulus of elasticity and modulus of rigidity are important parameters to measure mechanical properties of materials. With the aid of drawings, explain these parameters and gi

At which rate any part of a wave travels, Which of the answers listed below...

Which of the answers listed below best completes the statement: The rate at which any part of a wave travels from one place to another determines the waves: a) Propagati

How many types does heat transfer, How many types does heat transfer? ...

How many types does heat transfer? There are three ways of heat tranfer. a) Conduction (transfer of heat among objects in direct contact) b) Convection (transfer of he

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