Advanced Physics : Model Question Paper: BE II sem

Advanced Physics

Time: 2:00 Hours ]                                                                                                          [  Marks: 40 

INSTRUCTIONS TO CANDIDATES

   1)   All Questions carry Equal Marks as indicated.

(  2)   Solve FOUR questions as instructed.

(  3)   Assume suitable data.

   4)   Draw neat sketches wherever necessary.

   5)   Use of calculator is permitted.

Q1. (a) Write a note on Optical Pumping, Population Inversion                                  (4)

(b)Explain the mechanism of Ruby  LASER with the help of energy level diagram.  (4)

(c)Explain why the Lasing action is not possible in two level pumping scheme          (2)

OR

Q2. (a)What is thin film? Derive the expression for fringe width β i n interference pattern
            obtained in wedge shaped film.                                                                        (5)

 (b) State any two applications of Newton’s ring experiment.                                     (2)

 (c) Calculate the thickness of a calcite plate which would convert plane polarised light
       into circularly polarised light (μo= 1.658, μe= 1.486, light used is of 5893Å)    (3)

 Q3. (a)Explain why slower particles and faster Particles requires the same time for 
            completing one rotation in magnetic fields                                                        (2)

     (b)Discuss ht emotion of charged particles projected into uniform electric field
        at acute angle with the field direction and hence obtained the formulae for range,
        time of light and maximum height attained by the particle                                  (5)

    (c) A proton accelerates from rest in a uniform electric field of 500 V/m. At  
       some latter time its speed is 1.35 x 10 ⁶ m/s. Find i) Acceleration &
   ii) Time taken by the proton to reach the above speed.                                            (3)

OR

Q4. (a) Show that the electron moving with uniform velocity follows a parabolic
             path in a transverse uniform electric field.                                                     (3)

       (b)Explain the velocity filter with the help of cross field configuration.             (3)

       (c) What is magneto static deflection? Explain it with the help of following
           parameters  i) Deflection ii) deflection sensitivity.                                          (4)

Q5. (a) What is Bethe’s law? Discuss the refraction of electron beam across the
              boundary separating two equipotential regions.                                            (3)

      (b) Discuss the working of electrostatic lens and Electron Gun.                           (4)

      (c) Find out the kinetic energy of particle coming from a cyclotron having magnetic
               induction  10 ⁸ wb/m². Radius of the D is 3m.                                            (3)

OR

 Q6. (a) Draw the block diagram of CRO. Write the function of Trigger ckt.            (4)

        (b) Explain the working of Bainbridge mass spectrograph and deduce the 
             expression for the mass of particle.                                                                (3)

        (c) In a Bainbridge spectrograph the electric field used is 4 X 10 ⁴ V/m.

            (B = 0.55 Wb/m²) If the ion source consist of singly ionised neon isotopes of 
            atomic masses 20 & 22. Calculate the linear separation of the lines form
            on the photographic plates.                                                                               (3)

 Q7.(a)Explain the propagation of light in optical fibre find the expression for 
            acceptance angle in  optical fibre.                                                                  (3)                          

        (b)Discuss the types of optical fibre.                                                                 (3)

       (c)An optical fibre has NA of 0.33 & a cladding refractive index of 1.55. 
           Determine the acceptance angle for the fibre in water which has RI of 1.33.(4)

OR

 Q8.(a)How does the properties of nanomaterials differ from bulk materials?        (2)                 

       (b) Explain the structure of Graphne, compare it with the structure 
              of carbon.                                                                                                    (4)

       (c)Give the two applications of nano in materials in engineering.                    (4)