physics pass question paper Assam university fourth semester

physics pass question paper unit I a) find the expression for KE ans PE of a particle executing SHM and show that their sum is...

physics pass question paper

unit I

a)

1. find the expression for KE ans PE of a particle executing SHM and show that their sum is constant.
2. derive the equation  y = a sin (2π/λ)(ct-x)  for a plane progressive wave, where c is the wave velocity along the positive direction of x-axis.

b)

1. what is dipolar effect? derive an expression for the apparent frequency of a sound wave, whaen the source of sound approaches a stationary observer.
2. explain free vibration, forced vibration and resonance.

c)

1. write down the equation of a dimped oscillator and hence, obtain the general solution.
2. what aare beats and how are they formed?

d)

1. for a particle undergoing SHM, find the expression for its velocity and acceleration.
2. write short onte on:-  i) stationary waves and ii) Resonance.
   

unit II

a)

1. Obtain an expression for velocity of sound in homogenous medium and give Newton's formula for velocity of sound in gases
2. what are the low of vibration of a stretched string?

b)

1. establish that velocity of transverse wave in a stretched string is  v = √(T/M)
2. describe Kundt's tube experiment for the measurment of velocity of sound.

c)

1. Obtain an expression for the frequency of stationary waves formed on a strings. What is the frequency of the fundamental tone?
2. write down the Laplace's correction of Newton's formula for velocity of sound explain all terms.

d)

1. Describe Melde's experiment for generating stationary waves of a string.
2. the equation of a transverse wave travelling on a stretched string is given by  y = 10 sin π(2t - 0.01x), where, y and x are expressed in cm, and  t in second. Find amplitude, frequency, velocity and wavelength of the wave.
   

unit III

a)

1. deduce thye low of reflection using Fermat's principle.
2. describe Huygens eyepice, mention its advantages and disadvantages.

b)

1. what is longitudinal chromatic abrretion? show that for achromatic combination of twolenses, the distance between the two lenses should be arithmetic means of the focal length of the two lenses.
2. what is spherical abrreation? How is it minimized?

c)

1. State Fermat's principle. Describe the laws of refractin using Fermat's principle.
2. Discuss in berief the different types of aberration formed by lenses.

 d)

1. What are cardinal points? Discuss the cardinal points in berif.
2. Discuss a Ramsden eyepice with the help of a ray-diagram. what are its advantages.
   

unit IV

a)

1. explain the formation of newtons rings obtain due to reflection of monochromatic light. prove that the diameters of the dark rings are proportional to the square of roots of the natural numbers.

b)

1. how can you measure the thickness of a thin film by interference experiment.
   
2. describe the Lloyds mirror experiment for botaining interference fringes.
   
3. write the condition for getting sustained interference.

c)

1. what do you mean by division of amplitude and division of wavefront in regard to interference of light? give examples for both causes.
2. What would happen to the interference patteren if white light is used? give reasons.

d)

1. describe Frense's biprism apparatus for the measurement of wavelength of light.
2. How can you measure the thickness of a thin film by interference experiment?
   

unit V

a)

1. distinguish between Fresnel and Fraunhofer class of diffraction.
2. what is zone plate?  derive an expression for the focal length  of a zone plate and compare  it with  that of  a lense. 

b)

1. Describe Frensel's idea of half period zone, hence, give a qualitative discussion of Frensel's diffraction at a straight edge.

c)

1. Desctribe the construction of a Nicol prism Also, give its uses.
2. what are polaroids.

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