Download SGBAU BSc 2019 Summer 2nd Sem Physics Kintetic Theory Thermodynamics n Electric Currents Question Paper

B.Sc. (Part-I) Semester—II Examination

PHYSICS

(Kinetic Theory, Thermodynamics and Electric Currents)

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Time : Three Hours] [Maximum Marks : 80

Note :— (1) All questions are compulsory.

(2) Draw neat and well labelled diagrams wherever necessary.

1. (A) Fill in the blanks :
   1. Ballistic galvanometer measures the amount of ___________.
   2. Large Q value indicates the ___________ resonance.

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   3. Joule-Thomson effect is an ___________ process.
   4. In an adiabatic change the entropy ___________.
   (B) Choose the correct alternative :
   1. The numbers of degree of freedom for diatomic gas are :
      1. 3
      2. 5
      3. 7

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      4. 6
   2. When a charged particle moves in a transverse magnetic field, it traces
      1. Circular path
      2. Straight path
      3. Parabolic path

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      4. Irregular path
   3. Internal energy of an ideal gas depends upon
      1. Pressure
      2. Volume
      3. Temperature

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      4. Mass
   4. According to Kirchhoff's Law where the algebraic sum of current is zero ?
      1. In a linear network
      2. In a closed circuit
      3. At a junction

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      4. None of these
   (C) Answer in one sentence :
   1. What is j-operator ?
   2. What are the values of critical temperature of H₂ and O₂ gases ?
   3. Define current density.

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   4. What is specific heat ?
2. (A) State any four essential features of Brownian Motion.
3. (B) What are degrees of freedom ? Find degrees of freedom for monoatomic and diatomic molecules.
4. (C) Show that the average kinetic energy per mole per degree of freedom is ¹/₂ RT.

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OR

5. (P) Show that average kinetic energy of gas molecules is directly proportional to its absolute temperature.
6. (Q) Derive Van der Waal's equation of State of real gas.
7. (R) Obtain an expression for mean free path of the molecule of gas.

EITHER

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8. (A) State the first Law of thermodynamics.
9. (B) State and prove Carnot's Theorem.
10. (C) State second Law of thermodynamics in :
    1. Claussius form
    2. Kelvin ~ Planck form.

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OR

11. (P) Find the efficiency of Carnot's engine working between the steam point and the ice point.
12. (Q) What is P-V indicator diagram ? Explain the P-V indicator diagram for cyclic and non-cyclic process.
13. (R) Explain the terms :
    1. Reversible Process
    2. Irreversible Process.

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EITHER

14. (A) State the principle of regenerative cooling method.
15. (B) With the help of neat diagram, describe the method of liquefaction of hydrogen gas.
16. (C) Derive the thermodynamic relation

    (∂T/∂P)_H = (T(∂V/∂T)_P - V) / C_P

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OR

17. (P) With the help of neat diagram, describe the method of liquefaction of helium gas.
18. (Q) Describe the porous plug experiment and discuss its result.

EITHER

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19. (A) Explain the motion of charged particle in a transverse electric field.
20. (B) Explain the principle and working of Linear Accelerator.
21. (C) An electron moving in uniform magnetic field (B) is 20x10^-6 Wb/m² follows a circular path. If the orbital velocity is 4x10⁵m/s. Calculate the radius of orbit :

    [Given ; Mass of electron m_e =9.1x10^-31 kg ; Charge on electron (q)=1.6x10^-19 C]

OR

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22. (P) Explain the principle, construction and working of Cyclotron.
23. (Q) Explain the principle, construction and working of Bainbridge Mass Spectrograph.

EITHER

24. (A) State and explain Thevenin's theorem.
25. (B) Obtain an expression for the growth of current LR circuit.

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26. (C) State Kirchhoff's Current Law.

OR

27. (P) State and prove Maximum Power Transfer Theorem.
28. (Q) Enlist the physical quantities measured by galvanometer and ballistic galvanometer.
29. (R) Obtain an expression for growth of charge in a CR circuit when connected to a constant source of emf.

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EITHER

30. (A) What is series resonant circuit ?
31. (B) Explain the principle, construction and working of a transformer.
32. (C) Show that when an a.c. is applied to a pure inductor, the current lags behind the applied alternating voltage by π/2.

OR

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33. (P) Define the Quality Factor.
34. (Q) Derive an expression for the average power in an a.c. circuit.
35. (R) Using j-operator method obtain an expression for the current and impedance in series C-R circuit when ac is applied to it.

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