In this Paper Partnership graph was introduced.

 Like the above image, “partnership of error” graph was introduced. For example the error contribution by two parameters were mapped like the partnership of two batsmen in cricket. In this research work, the contribution of error from the subsurface layer inversion and resistivity values. When I was watching India-Australia Match, the concept arises and applied successfully using MATLAB software…

Neural Networks Base code with Pre processing and Post processing

load data.txt;
clc
P=data(1:12,1:2)
T=data(1:12,3)
a=data(13:20,1:2)
s=data(13:20,3)
[pn,minp,maxp,tn,mint,maxt]=premnmx(P',T')
[an,mina,maxa,sn,mins,maxs]=premnmx(a',s')
net=newff(minmax(pn),[5 1],{'tansig','tansig'},'traingdm')
net.trainParam.epochs=300;
net.trainParam.lr=0.3;
net.trainParam.mc=0.6;
net=train (net,pn,tn);
y=sim(net,an)
t=postmnmx(y',mins,maxs)
[t s]
plot(t,'r')
hold
% Current plot held
plot(s)
title('Comparison between actual targets and predictions')
d=[t-s].^2;
mse=mean(d)
[m,b,r]=postreg(t',s')

Mass spectrometer; Courtesy: www.schoolphysics.co.uk

Mass spectrometer

In 1919 Aston developed the first really good mass spectrograph, an instrument for measuring the masses of isotopes. His apparatus gave accuracies of one part in 1000.
A simpler form of the mass spectrograph than Aston's is that due to Bainbridge (1933) and a plan view of this is shown in Figure 1. 

Ions are formed at D and pass through the cathode C and then through a slit S₁. They then travel between two plates A and B, between which a potential (V) is applied. A magnetic field (strength B) is applied at right angles to the electrostatic field and so the electrostatic and electromagnetic forces act in opposite directions to each other. 

A particle with a charge q and velocity v will only pass through the next slit S₂ if the resultant force on it is zero – that is it is traveling in a straight line. That is if:

Electromagnetic force (Bqv) = Electrostatic force (qE)

Therefore, for the particle to pass through S₂: 

Velocity of particle (v) = E/B

But this is a constant, and so only particles with a certain velocity enter the deflection chamber F. For this reason the combination of slits and deflecting plates is called a velocity selector.
In the deflection chamber the ions are affected by the magnetic fields alone and so move in circular paths, the lighter ions having the larger path radius. If the mass of an ion is M, its charge q and its velocity v then:

Bqv = Mv²/r

where r is the radius of the path. Therefore r = Mv/(Bq)    and so: 

Mass of ion (M) = rB²q/E

The radius of the path in the deflection chamber is directly proportional to the mass of the ion.
The detection is by either a photographic plate or a collector that produces a small current when the ions fall on it. The magnetic field may be varied, so changing the radii of the particles' paths so that ions of different masses fall on a fixed collector.

This method of analysis is very accurate and can detect differences in the masses of two ions as small as one part in 10⁹.
Figure 2 shows the appearance of the photographic plate when a gas containing two isotopes is used. Note the wider line for the mass m₁, showing its relatively greater abundance.

Student investigation


Figure 3 represents the photographic plate taken from a Bainbridge mass spectrometer. It is drawn one-quarter full size and shows the collection of two different isotopes. Assuming that the isotopes are singly charged find
(a) the mass number of each of the isotopes,
(b) the gas used in the experiment.
The magnetic field across the apparatus is 0.01 T and the electric field in the velocity selector 100 Vm^-1.

 

Physics Syllabus Semester-1

ENGINEERING PHYSICS – I                                                                                                   L T P C

                                                                                                                                                 3 0 0 3

Aim: To explore various fundamental aspects of Physics.

Objectives

·         To understand the basic laws of physics and their applications in engineering and technology.

·         To develop scientific temper and analytical capability.

·         To solve various engineering problems.

url:www.schandgroup.com, www.google.com

UNIT-I: Acoustics                                                                                                                                                             9

Introduction, sound waves - Pitch and Intensity. Reflection of sound waves,  sabine formula, absorption of sound, reverberation Theory. Ultrasonics – production -  magnetostriction oscillator and piezoelectric oscillator. Properties and applications.

UNIT -II: Electron Optics                                                                                                                                               9

Introduction, Electron-refraction-Bethe’s law, Electron Gun and Electron Lens. Cathode Ray Tube and Cathode Ray Oscilloscope.  Cyclotron, Bainbridge Mass Spectrograph. Electron Microscope. Applications.                

UNIT -III: Crystal structures and X-Rays                                                                                                  9

Introduction, Space lattice, unit cell, lattice parameters, Bravais Lattice - Crystal systems. Characteristics of Unit cell (Cubic System). Miller indices of planes. X-Rays –production, Bragg’s Law. Powder crystal method and rotating crystal method.                     

                               

UNIT -IV:  Band Theory of Solids                                                                                                                               9

Introduction, Electrical conduction, conductivity, drift velocity, influence of external factors on conductivity. The Band Theory of solids, Energy Bands, Energy Gap. Classification of solids, Energy Band structure of a conductor. Fermi-Dirac distribution function and Fermi Energy. Energy Band structure of an Insulator and semiconductor.        

UNIT -V: Semiconductors                                                                                                                                             9

Introduction, Types- Intrinsic and Extrinsic semiconductors. Intrinsic carriers-electron and hole concentrations. Fermi level in intrinsic carrier density, Conductivity, Doping of impurities-N-type and P-Type. Temperature variation-law of mass action-Charge neutrality condition- Fermi level in extrinsic semiconductor-Hall effect. Applications- Semiconductor diode, Transistor, FET, MOSFET.                    

                                                                                                                                                Total: 45 periods             

Beyond the syllabus

Acoustics of buildings. Sonography,Cathode Ray Tube,Magnetic bottle

Modes of laser beam,Classification of hologram,Bragg’s X-Ray spectrometer,

Semiconductors in Electronics.

TEXT BOOK

1.       M.N. Avadhanulu and P.G. Kshirsagar ,A Text Book of Engineering Physics, S.CHAND and Co, 2012.

2.                Gaur and Gupta, Engineering Physics , Dhanpat Rai publications, 2009

REFERENCES

1.      S.O.Pillai ,Solid State Physics,New age international publications, 2010.

2.      M.Arumugam, Engineering Physics,Anuradha publications, 2009.

3.      Charles Kittel ,Introduction to Solid State Physics ,Wiley India publications, 2009.

4.      Introduction to Solids –L.Azaroff  TMH,33^rd Reprint 2009.

5.      Materials Science and Engineering – William Calister – Wiley India- Sixth Edition 2009.

Electron Optics Model Questions

Unit 2 - Electron Optics - One mark Questions

1) The bending of electrons by electric fields is called

a) Electron reflection

b) Electron refraction

c) Electron diffraction

d) Electronic bending

Ans: b

2) The most important component of an electron gun used for producing a narrow intense electron beam is

            a) Electron lens

            b) Electric field

            c) Glass lens

            d) Both a and c

Ans: a

3) The component used in the electron microscope which can converge an electron beam but cannot be used for diverging action. What is it?

            a) Electron lens

            b) Magnetic lens

            c) Fluorescent screen

d) Both a and b

Ans: b

4) The inner surface of the flare of the glass envelope of CRT (Cathode Ray Tube) is coated with conductive graphite coating called

            a) Acquadag

            b) Acquabag

            c) Radium

            d) None of the above

Ans: a

5) The interior surface of circular front of the CRT is coated with a thin translucent layer of fluorescent material. What is it?

            a) Phosphor

            b) Sulphur

            c) Radium

            d) Magnesium

Ans: a

6) What is the name of the transparent graph attached to the face of the CRT used for making measurements?

            a) Graticule

            b) Granule

            c) Graph

            d) Grains

Ans: a

7) What is the method of locking the frequency of the time base generator to the frequency of the input signal so that a stationary display of wave pattern is seen on the CRO screen?

            a) Deflection

            b) Synchronization

            c) Sweeping

            d) Triggering

Ans: b

8) ____________ is the only instrument that can give a visual display of the actual shape of the signal

            a) CRT

            b) Trigger circuit

            c) CRO

            d) None of the above

Ans: c

9) The trapped particles form radiation belts around the earth are called______

            a) Van Allen belts

            b) Magnetic belts

            c) Coastal belts

            d) Both a and b

Ans: a

10) Snells law describes refraction of light whereas Bethe’s law deals with

            a) Electron reflection

            b) Proton refraction

            c) Electron refraction

            d) Coherence of Laser

Ans: c

11) In the CathodE Ray Tube, the time taken by the sweep voltage to dip from its positive maximum to negative maximum value is called

            a) Fly back time

            b) Sweep period

            c) Trace time

            d) None

Ans: a

12) ________________ is used in Bainbridge mass spectrograph for separating positive ions of different masses.

            a) Velocity selector

            b) Momentum selector

            c) Isotope selector

            d) None

Ans: b

13) Beams of electrons can be deflected by electric and magnetic fields. Write True or False.

            a) True           b) False

Ans: True

14) The intrinsic property of the electron spin s is equals to 1/2. Answer True or False

a) True              b) False

Ans: True

15) In an external magnetic field the force of the electron is given by

                                     where v represents the

            a) Velocity of the electron

            b) Amplitude of the electron

            c) Frequency of the electron

            d) Magnetic field of the electron

Ans: a

Four mark questions

1) Discuss refraction of electron beam across an equipotential surface.

2) What is Bethe’s law? In what way it resembles and differs the Snell’s law.

3) Explain the working of electrostatic electron lens.

4) Explain the principle and construction of electron gun with neat diagram.

5) Draw the neat diagram of cyclotron and explain its principle and construction.

6) Draw the block diagram of CRO and discuss two applications.

7) Explain the working of magnetic lens.

8) Explain the principle of Bainbridge mass spectrograph with neat sketch.

9) Explain the construction of electron microscope with neat diagram.

10) Calculate the maximum energy to which deuterons can be accelerated in the cyclotron.

Given data are

            Magnetic Induction, B = 1.57 T

            Oscillator frequency, v = 12 x 10⁶ Hz

            Radius of the Dee, R = 21 Inch/0.53m

            Deuteron Charge, q = 1.602 x10^-19 C

Deuteron mass, m_d = 3.34 x 10^-27 kg

Mass Spectrometry; Courtesy:You Tube