PTU Important Questions----Theory Of Relativity

       Physics:

Important Questions related to chapter --Theory Of Relativity.

 2-marks/4-marks

Q1. Define frame of reference.
Q2. Explain the term time dilation.
Q3. Explain the concept of Ether.
Q4. Is earth an inertial frame? Explain briefly.
Q5. State the postulates of special theory of relativity.
Q6. Explain why a particle cannot move faster than velocity of light.
Q7. Define (a) Proper Length   (b) Proper Time
Q8. Show that relativistic law of addition of velocities predicts value of velocity
       of light in all inertial frames.
Q9. Prove that rest mass of photon is zero.
Q10. Photon has zero rest mass but has momentum. Explain.
Q11. Explain the term length contraction.
Q12. Prove that velocity of light is independent from the velocity of frame of reference.
Q13. What are the outcomes of Michelson-Morley experiment?
Q14. Find the velocity at which mass of a particle is double its rest mass.
Q15. Calculate the velocity of 1 Mev electron.
Q16. Why a moving rod appears shorter than its actual length?



6-marks/8-marks

Q1. (a)  Explain Michelson Morley experiment and discuss its significance.
       (b)  Explain various postulates of Special theory of Relativity.

Q2. (a) Explain the postulates of theory of relativity
       (b) Derive Lorentz's transformation equations.
      
Q3. Show that the mass of the body in motion is given by
                                                  
        where m0 is the rest mass and v is the velocity of the body.
Q4. (a) Prove that E= mc^2 . State its applications.
       (b) Show that no particle can have velocity greater than that of light.

Q5. (a) Derive the relation between relativistic energy and momentum.
       (b) Prove that momentum of a particle having rest mass and kinetic energy 'T' is equal to

PTU Important Questions----LASERS

                                   Physics:



Important Questions related to chapter --LASERS.


 2-marks/4-marks


Q1. What is laser?
Q2. What is holography?
Q3. Explain how a laser light is different from ordinary light?
Q4. Explain the terms:
      1)Stimulated emission 2) Population Inversion 3) Optical Pumping
      4)Stimulated absorption
Q5. State any four methods of pumping a laser.
Q6. Explain how a hologram differs from phtograph?
Q7. Explain spiking process.
Q8. Differentiate between spatial coherence and temporal coherence.
Q9. Differentiate between 3-level and 4-level laser.
Q10. Are all holograms same?
Q11.write physical significance of Einstein's coefficients.
Q12. Explain the role of Helium in He-Ne laser.
Q13. Differentiate between spontaneous emission and stimulated emission.
Q14.State any two applications of Holography.
Q15. Explain why a 4-level laser is preferred over 3-level laser although it has low efficiency?
Q16. What do you mean by coherance length? write down the expression for it.
Q17. What is the wavelength of He-Ne Laser, Semiconductor Laser?

6-marks/8-marks

Q1. a) Explain the construction, working and the energy level diagram for
           He-Ne laser.
       b) Explain process of spiking in Ruby laser.

Q2. a) Explain the construction, working and the energy level diagram for Ruby laser.
       b) Define Einstein coefficients and give their significance.

Q3. What do you understand by holography? Derive the relationship between
       Einstein coefficients.

image source: lasers.llnl.gov

Magnetic Materials & Superconductivity

Physics:

Important Questions related to chapter --Magnetic Materials and Superconductivity



2-marks/4-marks

Q1. Derive the relation b/w Permeability and Susceptibility.
Q2.State and explain the chief origin of magnetic moment for electrons.
Q3. State any four characteristics of ferromagnetic materials.
Q4. Define 1) Curie Temperature 2) Neel Temperature .
Q5. Define 1) Remanence 2) Coericivity .
Q6. What are ferrites? State few properties of ferrites. Give their useful applications.
Q7. What is magnetostriction?
Q8. What is magnetic anisotropy?
Q9. Differentiate b/w Soft and Hard magnetic materials.
Q10. Define 1) Magnetic flux density 2) Intensity of magnetisation .
Q11. Why ferromagnetism is lost on heating?
Q12. What is Meissners effect?

Q13. What do you mean by Cooper pairs?
Q14. Compare Type-I and Type-II superconductors.
Q15. Define critical magnetic field and critical temperature of a superconductor.
Q16. What is Superconductivity? Define persistent current.
Q17.  What is the difference b/w perfect Diamagnet and  Superconductor?


6-Marks/8-marks

Q1. State and explain Domain Theory of ferromagnetism.

OR

      Discuss domain structure in ferromagnetic materials.
Q2. i)Explain BCS theory of superconductivity.
      ii) Explain Meissner Effect.
Q3. What are London Equations? Explain the expression for the penetration depth of
       Superconductors.




Important questions related to chapter LASERS .
image source: personal.psu.edu

PTU Important questions--EM Waves and Dielectrics

Physics:

Important Questions related to chapter --EM Waves and Dielectrics.

2-marks/4-marks

Q1. Define gradient of a scalar field.Give its physical significance.
Q2. Define divergence of a vector field.Give its physical significance.
Q3. Define curl of a vector field.Give its physical significance.
Q4.What are solenoidal, irrotational and conservative fields?
Q5. Derive relationship b/w electric field and electric potential.
Q6. What is dielectric?Give its types. How a dielectric is different from an insulator?
Q7. Define dielectric medium and dielectric strength.
Q8. Explain the behavior of dielectric in external electric field.
Q9. Define polarization.

Q10. Define Poynting vector.
Q11. State Maxwell's equations and give their significance.
Q12.What are Em waves? Give their basic characteristics.
Q13. Derive the relation b/w dielectric constant and electric susceptibility.
Q14.Write short note on production of em waves.
Q15.Why light is characterized as electric vector, although it also possesses some
         magnetic vector.
Q16. What do you understand by displacement current?
Q17. Define electric susceptibility.

6-marks/8-marks

Q1. Derive wave equation for em wave in free space and show that em wave travels
       with speed of light.
Q2. "Maxwell equations are reformulation of existing laws." comment and
        justify your answer.

or

        Derive the relations for Maxwell's equation.

Q3. (a )What is polarization? What are its various types?Explain in detail.
       (b) Derive Maxwell equation as modified form of Ampere's law.




Important questions related to chapter Magnetic materials and superconductivity .
image source: tutorvista.com