PhD entrance examination – 2022 July

Subject: Physics

 

1. To determine the value of lagrangian, we assume

A) Kinetic energy         B) Potential energy       C) Both A and B          D) None of these

 

2. The lowest level energy band in a solid is called

A) Fermi level               D) Ground level            C) Valence band          D) Conduction band

 

3. The magnetic permeability is maximum for ________ material

A) Diamagnetic B) Paramagnetic           C) Ferromagnetic         D) All same

 

4. A method for the production of plane polarized light is

A) Reflection                B) Refraction                C) Double refraction     D) All of these

 

5. In the inverse piezoelectric effect, ______ waves are produced.

A) Electromagnetic       B) Infrasonic                 C) Ultrasonic                D) Micro

 

6. The wavefunction associated with a material particle is

A) Finite                       B) Continuous              C) Single valued           D) All the above

 

7. A thermodynamic process in which pressure remains constant is called

A) Isobaric                   B) Isothermal                C) Isotropic                  D) Isocyclic

 

8. How many ways can the Hamilton’s equation be derived?

A) 1                             B) 2                             C) 3                             D) 4

 

9. To solve Schrodinger equation, we need potential and

A) Boundary conditions                                                B) Physical requirements of system       

C) Both A and B                                                          D) None of these

 

10. An example for bottom-up approach synthesis of nanomaterials is
A) Lithography                                                 B) Sol gel method

C) High energy ball milling                                 D) None of these   

 

11. What is the percentage of free space in a body centered cubic crystal unit cell?

A) 68%                        B) 32%                        C) 74 %                       D) 26%

 

12. In a metal, temperature (X-axis)-resistivity (Y-axis) graph shows

A) Positive slope                                                          B) Infinite slope                       

C) Negative slope                                                         D) Zero slope

 

13. Which one of the following is most essential for observing diffraction of light?

A) Monochromatic light                                                B) White light                          

C) A very narrow slit or obstacle                                  D) Two coherent sources

 

14. For T = 200K, probability of occupancy of Fermi level value below Fermi level can be 

A) 0                             B) 0.99                        C) 0.01                        D) Infinite

 

15. Which one of the following is true for metals?

A) Resistance is temperature dependent

B) Obey Ohm’s law

C) Both A and B are wrong

D) Both A and B correct

 

16. The role of He in He-Ne laser is

A) He is an active medium                                            B) Population inversion takes place in He

C) Stimulated emission takes place in He                       D) He atoms helps in exciting Ne atoms

 

17. Which one of the following has highest intermodal dispersion?

A) Step index single mode                                            B) Step index multimode          

C) Graded index multimode                                          D) All have same intermodal dispersion

 

18. Which of the following is not an amorphous material?

A) Plastic                     B) Lead                        C) Rubber                    D) Glass

 

19. Which of the following is described by the concept of numerical aperture in an optical fiber?

A) Light scattering        B) Light collection         C) Light deviation         D) Light polarization

 

20. The unit of permittivity is

A) Farad/m                  B) Farad-m                  C) Farad/m²                 D) Farad-m²

 

21. In an optical fiber, light propagates in the

A) Core                       B) Cladding                  C) Jacket                     D) None of these

 

22. An electron and a proton are accelerated through same potential. The ratio of de-Broglie wavelength  is

A) 1                              B)                           C)                            D)

 

23. In canonical transformation, the set of variables obey

A) Pythagorean theorem                                               B) Hamilton’s equations           

C) Newton’s laws                                                        D) Law of thermodynamics

 

24. Which statistics follows Pauli’s exclusion principle?

A) Fermi-Dirac                                                 B) Maxwell-Boltzmann

C) Bose-Einstein                                                          D) All of these

 

25. The Andromeda galaxy is which of the following types of galaxies?

A) Elliptical                   B) Spiral                       C) Barred-spiral           D) Irregular

26. Which one of the following is a structure of CNT?

A) Armchair                 B) Zig-zag                    C) Chiral                      D) All of these

 

27. Orientation polarization occurs

A) In all dielectrics                                                        B) In polar dielectrics

C) In non-polar dielectrics                                            D) In ionic dielectrics

 

28. Momentum of a moving body

A) Depends upon its mass alone

B) Depends upon its velocity alone

C) Depends upon its mass and velocity

D) No dependence on its mass and velocity

 

29. Which of the following waves/rays are produced by nuclear changes in the atom?

A) Infrared rays            B) Ultrasonic waves      C) Gamma rays            D) X-rays

 

30. Carrier wave which is used in long distance communication is
A) Radio waves                                                            B) Microwaves

C) Light waves                                                             D) All of these

 

31. Which of the following are the properties of superconductors?

A) They are diamagnetic in nature                                 B) They have zero resistivity     

C) They have infinite conductivity                                  D) All of the above

 

32.  The magnetism left in the iron after exciting field has been removed is known as

A) Residual magnetism                                      B) Coercivity   

C) Flux density                                                 D) Susceptibility

 

33. X-rays are generated by

A) Ionization chamber                                       B) Avalanche photodiode

C) Electrometer                                                            D) Coolidge tube

 

34. The phenomenon of Newton’s rings can be used to check the __________.

A) Wavelength of monochromatic light             B) Phase coherence of two sources

C) Flatness of any glass surface                                     D) Velocity of light

 

35. A proton and an alpha particle are accelerated through the same potential difference V. The wavelengths associated with these two particles will be in the ratio

A) 1:2                          B) 2:1                           C) 4:1                          D) None of these

 

36. If the momentum of an object increases by 20%, its kinetic energy will increase by,

A) 66%                        B) 77%                        C) 44%                        D) 55 %

 

37. The region of electromagnetic spectrum for nuclear magnetic resonance is

A) Microwave              B) Infrared                   C) Radio frequency      D) UV rays

 

38. When electrons are trapped in the crystal lattice in place of anion vacancy, the defect in the crystal is known as

A) Non-stochiometric defect                                         B) Stochiometric defect           

C) F-centre                                                                  D) Frenkel defect

 

39. The speed of light will be minimum while passing through

A) Vacuum                   B) Water                      C) Air                          D) Glass

 

40. Which one of the following common devices works on the basis of the principle of mutual induction?

A) LED                        B) Photodiode              C) Transformer D) Transistor

 

41. The power of a lens is measured in

A) Decibel                    B) Watt                        C) Candela                   D) Dioptre

 

42. A ferroelectric crystal loses spontaneous polarization at

A) Transition temperature                                             B) Fermi temperature

C) Curie temperature                                                    D) Debye temperature

 

43. If the function neither satisfied even parity & odd parity, then function is said to be

A) Indefinite parity                                                        B) Symmetric potential 

C) Degenerate state                                                      D) None of these

 

44. In Rutherford scattering experiment, the path of the scattered particles is

A) Hyperbolic              B) Parabolic                 C) Elliptical                   D) Circular

 

45. An astronaut at rest has a heart rate of 65 beats/min. When the astronaut’s spaceship moves at a speed of 0.6c, her heart rate in beats/min as measured by an earth observer will be:

A) 26                           B) 52                           C) 74                           D) 104

 

46. Doppler effect in sound produces apparent change in

A) Wavelength B) Intensity                   C) Frequency               D) Amplitude

 

47. The number of independent ways in which a mechanical system can move without violating any constraint is called

A) Degrees of freedom                                     B) Number of freedoms           

C) Generalized coordinates                                           D) Wavefunctions

 

48. The transition zone for Raman spectra is

A) Between electronic levels                                         B) Between magnetic levels of unpaired electrons

C) Between magnetic levels of nuclei                 D) Between vibrational and rotational levels

 

49. In which direction, the recoil electron in Compton scattering has the maximum kinetic energy?

A) 0⁰                            B) 90⁰                          C) 180⁰                        D) 270⁰

 

50. The equation of the plane that is tangent to the surface xyz=8 at point (1,2,4) is

A) 4x + 2y+ z =12       B) x + 2y+ 4z =12        C) x + 4y+ 2z =12       D) x + y+ z =7