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)

CRO II - To measure Phase shift between the two Sinusoidal Signal:Practical - BSc V SEM

Aim : To measure Phase shift between the two Sinusoidal Signal.

Apparatus : CRO (Cathode Ray Oscilloscope), Function Generator, cods, Resistance box, capacitance box etc
Formula :     Phase shift = tan^-1(1/2πf C R)
                       Phase shift = (Δ x/x) 360⁰
  where,                    

  C - Capacitance
  R - Resistance

 Δ x - Divisions (Peak of y signal to Peak of X signal)  
     x - Divisions (Peak to Peak of Y signal)

 f - Frequency from function Generator  

Diagram : (circuit)

Procedure : 

Calculation of Phase shift

1) Switch ON CRO , keep it in duel Mode.
2) Adjust Focus , intensity, can role knob and CH1, CH2 position knob to get two sharp horizontal trace on CRO.
3) Make connections as shown in figure.

4) Now set the time/div and v/div knobs of CH1 and CH2 to get suitable waveform.
5) Align both the sine waves of CH1 and CH2 for selected frequency from function Generator in the interval of 500 Hz.

6) Set the Sine wave on the screen of CRO for both the signals and measure Peak to peak distance between CH1 and CH2.( Δ x )

7) Take the peak to peak distance of CH1's sign wave as x.

8) Multiply the ratio above readings by 360⁰. We get calculated Phase Shift.

9) Take the theoretical value of Phase shift. We get theorotical Phase Shift.

10) Finally check whether this calculated value of  phase shift is matched with the theorotical Phase Shift or not.
11) Repeat the above procedure for another combination of R and C.

Observation Table : 

Sr. No.	Applied Frequency (F.G.)	R	C	Δ x	x	Phase shift = tan-1 (1/2πf C R)	Phase shift = (Δ x/x) 3600
1.
2.
3.
4.
5.

Table : Calculation of Phase Shift

 Result : The Practical values of  Phase Shift and the theoretical Phase Shift are in good agreement or different combinations of f, C, R.

Precautions :1) Do not use CRO in dusty condition.2) The knobs of CRO are in released Position.3) Do not increase the brightness of CRO, it not necessary.

CRO I - Calibration of Sine Wave:Practical- BE II SEM - ADVANCED PHYSICS

Aim : To Calibrate the Sinusoidal Wave

Apparatus : CRO (Cathode Ray Oscilloscope), Function Generator, cods etc
Formula :     T = t X Δ x     

                      Frequency= 1/ T = f   

  where,     t - times per divisions (reading)

 Δ x - Divisions (Peak to Peak difference)  

 f - Frequency from function Generator  

Diagram : (circuit)

Procedure : 

Calibration of Sinusoidal Wave

1) For Calibration of the Sinusoidal wave make the connections as shown in figure.

2) Check whether all the knobs of CRO are in released Position.

3) Now set the frequency from function Generator in the interval of 500 Hz.

4) Set the Sine wave on the screen of CRO such that only 2 to 3 peaks should be seen on the screen of CRO.

5) Take the peak to peak distance of sign wave as Δ x.

6) Multiply Time/div by the divisions i.e by Δ x. We get T(Time).

7) Take the reciprocal of Time. We get Frequency.

8) Finally check whether this calculated value of frequency is matched with the frequency from function generator or not.

Observation Table : 

Sr. No.	Applied Frequency (F.G.)	Time/div (a)	Peak-peak distance(b)	Time  T= (a) X (b)	Frequency F = 1/T
1.
2.
3.
4.
5.

Table: Measurement of Frequency by calibration of sine wave.

 Result : The Practical values of frequency and frequency from function generator are in good agreement. So for each value of selected frequency sine wave is calibrated.

Precautions :1) Do not use CRO in dusty condition.2) The knobs of CRO are in released Position.3) Do not increase the brightness of CRO, it not necessary.

Foundation course after 10th - Foundation Pitch