Bragg''s law and calculation of wavelength, Other Engineering

Q. Explain Bragg's law. A monochromatic X-ray is incident on a crystal. By rotation the crystal, two successive reflections are obtained at angles of 10.0° and 23.0°. the inter planer spacing of the crystal is 2.8 À. Calculate the wavelength of X-ray.

Bragg's Law : In  1912, Bragg developed a theory to explain the diffraction by a crystal grating. He supposed that the incident wave undergoes reflection at various parallel plane of atoms in the crystal, with each plane reflect a small part of incident radiation according to ordinary laws of reflection. The diffracted beams are found only when the various plane of atom interfere constructively.

Let us consider a set of parallel atomic plane in a crystal separated by a distance'd' known as interplaner spacing. Let a X ray beam is incident at a glancing angle q. It is scattered by the atom like P and Q in any direction.

Constructive interference will take place between the parallel scattered wavelets if the path difference between the wavelets scattered from two successive atomic plane is integral multiple of wavelength.

Consider two parallel rays R1 and R2, reflected by two atoms P and Q in two adjacent layers. The ray reflected from P goes to R1' and from Q goes to R2'. Draw PA and PB normal to R2 and R2' respectively. Each of these lines, makes an angle q with PQ which is equal to d (inter planar spacing).

 

 

Posted Date: 7/11/2012 2:51:55 AM | Location : United States







Related Discussions:- Bragg''s law and calculation of wavelength, Assignment Help, Ask Question on Bragg''s law and calculation of wavelength, Get Answer, Expert's Help, Bragg''s law and calculation of wavelength Discussions

Write discussion on Bragg''s law and calculation of wavelength
Your posts are moderated
Related Questions

When light of frequency greater than threshold frequency fall on a metal surface, electrons are emitted out from metal surface this effect is known as photoelectric effect. Laws

Explain and identify the different sources of finances which are available to businesses and which sources of finance are internal sources and which are external sources?

Means of escape - place of safety: The means of escape in a building are often supplemented by a fire warning system that may or may not include automatic detection, depending


Differentiator: With negative feedback applied through a resistor and the input signal through a capacitor, the circuit will perform the mathematical operation of differentiati

The phugoid is a relatively low-frequency oscillation in which kinetic and potential energies are exchanged. The mode is generally characterized by low damping and approximately co

Fire fighting operations - high rise buildings: Inlets that allow the fire service to supplement to water to the sprinklers and to the fire mains are useful additions to the m

State Vectors  In engineering - particularly control engineering - most systems are represented by a state vector.  - The state vector contains all of the relevant qua

A steak which is 2.5cm thick is cooking in a frying pan which has a 4mm thick base. The electric element used to heat the pan is turned to a level such that the bottom surface of t