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Tutorial SheetsDEPARTMENT OF PHYSICSIst YEAR B TechSubject : ENGG. PHYSICSUnit Name : Coherence, Young’s Double Slit

CET2007-08

Code : 104

Tutorial Sheet No : 1 Name of Student ……………………………..

Topic : ………………………………….Date of Submission : ………………….

Tutorial

class questi

ons (20

MT)

Q.1 What is coherence? Explain temporal and spatial coherence.

Q.2 State the Principle of Superposition.

Home Assignment

s (Max. time

2 hrs.)

Q.1 The spectral spread of a laser light 6943Å is 0.0001Å. Calculate spectral purity factor, coherence length and coherence time.

Q.2 If the coherence length of a laser source is 100cm and the wavelength used in it is 6328Å; calculate the bandwidth and frequency spread.

Q.3 Discuss the interference of waves by two synchronous sources, hence find (i) the expression for the fringe shift. (ii) The intensity distribution in fringes.

Other Important

Questions

Q.1 Two narrow and parallel slits 0.08 cm apart are illuminated by light of frequency 6x10-4 KHz. It is desired to have a fringe width of 6x10-4 m. Where the screen should be placed from the slits?

Q.2 In a biprism experiment, the obtuse angle of the biprism is 178° and μ = 1.524. If slit to biprism distance is 5.0 cm and biprism to screen is 65.0 cm, calculate the fringe width for light of wavelength λ = 5893 Å.

Q.3 In an interference pattern, at a point we observe 12 th order maximum for λ1 = 6000 Å. What order will be visible here if the source is replace by light of wavelength λ2 = 4800 Å?

Note : 1. Every student must have the tutorial sheets with them when attending tutorial classes.2. Students must have separate loose sheet or a separate test copy with them as specified.

The only place where success comes before work is in the dictionary.

Tutorial SheetsDEPARTMENT OF PHYSICSIst YEAR B TechSubject : ENGG. PHYSICSUnit Name : Fresnel’s Biprism, Thin Film

CET2007-08

Code : 104



Tutorial

class questi

ons (20

MT)

Q.1 How shall you measure thickness of thin silicon chip using Biprism experiment?

Q.2 Why a thin film illuminated with white light exhibits many colours?.

Home Assignment

s (Max. time

2 hrs.)

Q.1 Prove that for thin films, the interference patterns in reflected and transmitted light are complementary.

Q.2 Illustrate the formation of interference fringes in fresnel’s biprism. Show how would you use this to determine the wavelength of monochromatic light?

Other

Important Questions

Q.1 In a biprism experiment, an interference pattern is seen on the screen placed at a distance of 1m from slits. The distance between the slits is 0.5mm. A thin glass plate of thickness 1.5 μm and refractive index μ = 1.5 is placed between one of the slits. Find the lateral shift of the central maximum. Also find the intensity at the center of the screen. Wavelength of light used is 5000 Å.

Q.2 In a biprism experiment the micrometer readings of zero order fringe and tenth order fringe are 2.37mm and 3.55mm resp. Wavelength of light used is 5890 Å. Determine (i) The position of zeroth and 10th order fringe when λ changes to 7500 Å. (ii) The position of zeroth order fringe when mica sheet of thickness 0.02mm and μ = 1.5 is introduced to cover half of the prism.



Tutorial SheetsDEPARTMENT OF PHYSICSIst YEAR B TechSubject : ENGG. PHYSICSUnit Name : Newton’s Ring

CET2007-08

Code : 104

Tutorial Sheet No : 3Name of Student ……………………………..


Tutorial

class questi

ons (20

MT) Q.1 Why circular fringes are formed in Newton’s rings arrangement?

Q.2 Discuss why central rings are broad and peripheral rings are closer in Newton’s rings experiment.

Home Assignment

s (Max. time

2 hrs.)

Q.1 Give theory of Newton’s rings? How they used to find (i) wavelength of light (ii) refractive index of liquid.

Q.2 Explain what happens to Newton’s when (i) the lower glass plate is rough and not plane (ii) The lens is not in contact with the glass plate (iii) Some oil is placed between the glass plate and lens.

Other

Important Questions

Q.1. In a Newton’s rings experiment, the diameter of nth and (n+8)th rings were 4.2mm and 7.0mm. If the radius of curvature of the lens is 2m, then find the wavelength of light used.

Q.2 In a Newton’s ring experiment the diameter of the 10th bright ring changes from 1.40cm to 1.27cm. When a liquid is introduce between the plate and the lens. Calculate the refractive index of the liquid.



Tutorial SheetsDEPARTMENT OF PHYSICSIst YEAR B TechSubject : ENGG. PHYSICSUnit Name : Michelson Interferometer

CET2007-08

Code : 104



Tutorial

class questi

ons (20

MT) Q.1 Draw labeled diagram of Michelson’s Interferometer.

Q.2 Discuss circular fringes obtained in Michelson Interferometer and compare them with Newton’s rings.

Home Assignment

s (Max. time

2 hrs.)

Q.1 Describe the construction and working of Michelson Interferometer. How would you use it to measure the wavelength of the monochromatic light?

Q.2 Discuss the important application of the Michelson’s Interferometer.

Other

Important Questions

Q.1 In Michelson’s Interferometer when the mirror is displaced through a distance of 2.948 x 10-5m; 100 fringes cross the field of view. Determine the wavelength of light used in this experiment.

Q.2 In Michelson’s Interferometer experiment, the distance moved by the moveable mirror between two consecutive positions of maximum distinctness is 0.2945mm. If the mean wavelength of the two component of the D-line is 5893Å. Determine the difference between the wavelengths.



Tutorial SheetsDEPARTMENT OF PHYSICSIst YEAR B TechSubject : ENGG. PHYSICSUnit Name : Wave Mech. (Sch eq”)

CET2007-08

Code : 104



Tutorial

class questi

ons (20

MT) Q.1 On the basis of uncertainty principle shows that the electron cannot exist inside the

nucleus of an atom. Does the same argument apply to the proton? Explain.

Q.2 What is the physical significance of the wave function?.

Home Assignment

s (Max. time

2 hrs.)

Q.1 State Heisenberg’s uncertainty principle and illustrate it’s validity by any thought Experiment.

Q.2 State the energy time uncertainty principle and explain the natural width of spectral line.

Q.3 Derive Schrodinger time independent wave equation for free and bound particle and give it’s physical interpretation?

Other

Important Questions

Q.1 What is the uncertainty in the location of a photon if its wavelength of 5000 Å is known to an accuracy of one part in 107 ?

Q.2 An electron has a speed of 300m/s, accurate to 0.01%. With what fundamental accuracy can we locate the position of the electron?

Q.3 The velocity of (i) an electron (ii) a proton is 106 m/s and the fundamental error in its measurement is 0.01%. Calculate the fundamental error in the measurement of its position? Given mass of electron = 9.1* 10-31 kg. And mass of proton = 1.67* 10-27kg.



Tutorial SheetsDEPARTMENT OF PHYSICSIst YEAR B TechSubject : ENGG. PHYSICSUnit Name : 1-D, 3-D Potential Barrier

CET2007-08

Code : 104



Tutorial

class questi

ons (20

MT)

Q.1 Explain the following :(i) Hamiltonian(ii) Expectation value(iii) Normalized and orthogonalized wave function

Q.2 Write down Schrodinger equation for a free particle of mass m trapped in 1-D box of side ‘a’ Solve it for energy eigen value and eigen function.

Home Assignment

s (Max. time

2 hrs.)

Q.1 Modify 1-D Schrodinger equation in 3-D cubical box of side ‘a’ and hence explain the term degeneracy?

Find lowest energy of the following states :(i) Double degenerate(ii) Triply degenerate(iii) 6-fold degenerate for 3-D cubical box

Q.2 What is tunnel effect? For potential barrier problem find out the transmission coefficient of a particle having less energy than the height of potential Barrier?

Other

Important Questions

Q.1 A particle is moving in a 1-D box of infinite height of width 10Å at the center of the box, when it is in its state of least energy?

Q.2 In a long chain organic molecule of length 5Å electron may be treated as free to move along the length. Deduce the zero point energy and the energy gap between the 1st two energy state of the electron and also the wave length of absorption line arising from this transition?

Q.3 Calculate the lowest energy of an electron confined in a cubical box of side 1Å each.



Tutorial SheetsDEPARTMENT OF PHYSICSIst YEAR B TechSubject : ENGG. PHYSICSUnit Name : WAVE MECH.(Density of state, Fermi State)

CET2007-08

Code : 104

Tutorial Sheet No : 12Name of Student ……………………………..


Tutorial

class questi

ons (20

MT) Q.1 What is density of states in metals? Derive an expression for the density of energy states

and hence Fermi energy of metals?

Q.2 What you mean by Fermi energy, Explain it’s importance?

Home Assignment

s (Max. time

2 hrs.)

Q.1 Calculate Fermi energy in Cu assuming that each Cu atom contribute 1 electron to the electron gas? Given density of Cu = 8.94*103 Kg/m3 atomic mass is 63.5u.

Q.3 There are 2.54x 1022 free electron per cm3 in Na. Calculate Fermi energy, Fermi velocity and Fermi temp?

Other

Important Questions Q.1 The Fermi energy for Li is 4.72 eV at T=0K. Calculate the no. of conduction electron

per unit vol. In Li.?



Tutorial SheetsDEPARTMENT OF PHYSICSIst YEAR B TechSubject : ENGG. PHYSICSUnit Name : Polarization

CET2007-08

Code : 104



Tutorial

class questi

ons (20

MT) Q.1 What is polarization? How the polarized light can be differentiated from ordinary light?

Q.2 Explain how would you produced plane polarized light by refraction through a pile of plates.

Home Assignment

s (Max. time

2 hrs.)

Q.1 Explain the term :(i) Polarized light(ii) Plane polarized(iii) Plane of Vibration(iv) Optic axis(v) Principle plane

Q.2 Give various methods for producing plane polarized light?

Q.3 State Brewster’s Law and use it to prove that when light is incident on a transparent plate at the polarizing angle, the refracted and reflected ray is at right angle to each other. How it can be used to produce plane polarized light.

Q.4 State and explain the law of Malus.

Other

Important Questions

Q.1 A ray of light is incident on the surface of a glass plate at the polarizing angle.

Q.2 Find the polarizing angle for the light incident from (i) Air to glass (ii) Glass to air (iii) Water to glass (iv) Glass to water (v) Water to air.

Q.3 Two polarizing sheets have their polarizing direction parallel so that the intensity of transmitted light is maximum, through what angle must either sheet be turn so that the intensity become one half of initial value.

Q.4 The critical angle for certain wavelength of light in the case of glass is 40. Find the polarizing angle for glass.

Q.5 Two nicol prisms are arrange so that the amount of light transmitted through them is maximum. What will be the %age reduction in the intensity of incident light when analyzer is rotate through 30º to 45º.




CET2007-08

Code : 104



Tutorial

class questi

ons (20

MT)

Q.1 Explain the phenomena of Double refraction.

Q.2 What does you mean by quarter wave plate and half wave plate? How will you distinguish between them?

Home Assig

nments

(Max. time

2 hrs.)

Q.1 Describe the construction and working of nicol prism. Explain it’s working as polarizer and analyzer. Can a similar quartz plate serve the same purpose?

Q.2 Explain the meaning of plane polarized, circularly polarized and elliptically polarized light? Prove that plane and circular light are the special case of EPL.

Q.3 How would you produce and detect PPL CPL EPL? How would you distinguish CPL from unpolarized light, EPL from a mixture of PPL? Also give the theory of Instrument used for the same.

Q.4 What will be the state of polarization of the emergent when :i) A beam of CPL is passed through a QWP.ii) A beam of PPL is passed through a QWP.iii)A beam of EPL is passed through QWP.iv)A beam of PPL is passed through a QWP such that the vibration of PPL is falling

on the QWP make an angle of 45º with its optic axis.

CONTD..2..

..2..

Other

Important Questions

Q.1 A partially polarized light beam is passed through a nicol prism. In 90º rotation of nicol prism, the intensity changes from I(m) to 0.31(m). Find the degree of polarization.

Q.2 Calculate the thickness of a double refracting crystal required to introduce a path difference of λ /2 bet. O-rays and E-rays, when λ = 6000A, μ(o) = 1.55 and μ(e) = 1.54.

Q.3 A beam of linearly polarized light is changed into CPL by passing it through a sliced crystal of thickness 0.003 cm. Calculate the difference in refractive indices of the two rays in the crystal assuming this to be minimum thickness that will produce the effect. The wavelength of light is used is 6 x 10-7m.

Q.4 The faces of quartz plate are parallel to the optic axis of the crystal.i) What is the thinnest possible plate that would serve to put the O-ray and E-ray of λ

= 5890A a half wave apart on their exit.ii) What multiple of this thickness would give the same result?

μ(o) = 1.544 and μ(e) = 1.553 for quartz.

Q.3 A phase retardation plate of quartz has thickness 0.1436mm for what wavelengths in the visible region will it act as 1. QWP 2. HWP.




CET2007-08

Code : 104



First 20

min. class

question

(write answer on loose sheet)

Q.1 What is optical rotation? Explain the term laevorotatory and dextro-rotatory..

Q.2 What is Laurent’s half shade and Biquartz Plate.

2 hrs. solvab

le home work questi

on

Q.1 What is optical activity? Mention the law of optical rotation?

Q.2 How will you differentiate between PPPL, EPL and mixture of UPL and CPL?

Q.3 Define specific rotation. Describe the construction and working of a Laurentz half shade polarimeter to determine optical rotation.

Q.4 Explain the working of Biquartz polarimeter. How would you use it to find the specific rotation of any optically active substance?

Other Important

Questions

Q.1 A 20cm long tube containing sugar solution is placed between crossed Nichol and illuminated by light of wavelength = 6000 Å. If the specific rotation is 60 and optical rotation is 12º, what is the strength of solution?

Q.2 Calculate the specific rotation of solution, when :(i) Length of tube is 20cm(ii) Vol. = 120cm3

(iii) Quantity of sugar – 6 gm(iv) Angle of rotation of the analyzer for restoring equal intensity = 6.6º

Q.3 A 200cm tube containing 48cm3 of sugar sol. Produces an optical rotation of 11 when placed in a sacchaerimeter. If the specific rotation of solution is 66, calculate the quantity o sugar in tube.

Q.4 If 20cm length of certain sol. Causes right-handed rotation of 42º and 30 cm of sol. Causes left handed rotation 27º, what rotation will be caused by 30cm length of a mixture of the above solution in the volume ratio of 1:2.

Q.5 The μ of quartz for left and right handed circularly polarized light propagate along the optic axis are 1.54420 and1.54427 the wavelength of Na light –6x10-5cm.



Tutorial SheetsDEPARTMENT OF PHYSICSIst YEAR B TechSubject : ENGG. PHYSICSUnit Name : LASER

CET2007-08

Code : 104



First 20

min. class question

(write

answer on loose sheet)

Q.1 Explain the term population inversion and optical pumping. How can this be achieved in Ruby laser?

Q.2 Give briefly the requirements for holography. What advantage does hologram possess over an ordinary photograph?

2 hrs. solvable

home work question

Q.1 Describe a Ruby Laser and explain its working showing its effective energy levels?

Q.2 What is essential requirements to produce a laser. Describe with neat sketch how are these fulfilled in He-Ne Laser?

Q.3 Describe the method of recording the hologram and reconstruction of image from it?

Q.4 Give elementary idea of optical fiber and obtain an expression for the numerical aperture of a step index fiber.

Other

Important Questions

Q.1 Explain the term absorption, spontaneous emission and stimulated emission and derive a relation between Einstein’s coefficients?

Q.2 Mention difference between spontaneous emission and induce emission. Does laser action depends on them?

Q.3 Give construction of optical fiber and discuss the phenomenon on which it work for guided transmission?

Q.4 A typical optical fiber (n=1.5) with cluding (n=1.4) is used in a water (n=1.33) environment determine

(i) The numerical aperture(ii) The max. Acceptance angle


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