# Mumbai University Previous year question papers

## Applied Physics-II

N.S.: (1)

Question No.1 is compulsory.

(2) Solve any four questions from Q. Nos. 2 to 7.

(3) Usesuitable data wherever necessary.

(4) Figures to the right indicate full marks.

1. ,Solve any five from the following :-

(a) Why are Newton’s rings are circular?

(b) What do you mean by diffraction and state its types?

(c) What do you meanbyVacuum? What are variousgaugesusedto measure Vacuum?

(d) What is Biophysics? Discuss its scope.

)e) Define relative permeability and susceptibility. Write the relation between them.

(f) Find the energy of neutron in units of electron volt whose DeBrogllie wavelength is 1AO(Givenmn=1’674x 10-27kg, h = 6.62X10-34J.sec.).

(g) What is pumping in LASER? Give the’ types of pumping.

(h) Define the terms: (i) Total Internal Reflection.

(ii) Numerical Aperture (NA)

(iii) Acceptance Angle.

2.(a) Provethat in Newtonsring experiment diameter orntn dark ring is proportional to What will be the ring number which will have double the diameterthat of 4(jth dark ring?

(b) What do~~he word LASER stand for? Explain the following te ‘s related to LASER w~ppropriate figures (i) Absorption (ii) Spontaneou~ emission

(iii) Stimulated absorption.

3. (a) DeriV~one-dimensional time dependent Schorodinger equation for Matter Waves.

(b) White ‘light falls normally on a soap film of thickness 5 x 10-5 tm and of ,refractiveindex1.33. Whichwavelengthin the visibleregion will be reflected most strongly?

4. (a) What is Holography? Explainthe constructionand reconstruction of  hologram.

(b) Calculate the numerical aperture and hence the acceptance angle for an optical fib~e given that refractive indices of the core and the cladding are 1-45,md 1-40 respectively. ‘

5. (a) Explain various stages of Hysteresis curve and give the significance of Hysterosis.

(b) How many orders will be observed by grating having 4000 lines per em, if it is illuminated by light of wavelength in the range 5000 AOto 7500 AO.

6. (a) Showthat electron can not pre-exist in free state in a nucleus.

(b) A magnetic material has magnetizing force 198 Aim and magnetization of 2300 Aim, find

(i) Corresponding flux density (ii) Relative permeability

(Given Ilo = 4n x 10-7).

7.. ~a) Givethe applicationsof the followinginstrumentsUV,IR,NMRand Microscopy?

(b) Explain the construction and working of Pirani gauge.