DR. BABASAHEB  
AMBEDKAR  
TECHNOLOGICAL  
Chemical,  
UNIVERSITY,  
LON ERE  
First Year B. Tech. (Mechanical,  
Civil and Petrochemical)  
End Semester Examination  
Subject: Engineering Physics  
-201'1.  
Maximum  
Marks:  
60  
:
- hour  
enggsolution.com  
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9APA 2017  
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Instructions  
to the sludcnts:  
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.
All qut:stions are ~ompulsory and each question carries 10 marks  
Illustrate your answers \\lith neat sketches. diagrams etc. wherever necessary.  
Necessary data is given in the respective questions. Ifsuch data is not given, it mean~ that the kno\'.'ledge of  
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tile pan is part of examination  
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..J.  
If some part or parameter is noticed to be missing, you may appropriately  
assume it and should mention it  
clearly.  
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Q.I Attempt the following.  
a) Obtain the differcntial equation of damped oscillation and find its general solution.  
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b) Calculatc the natural frequency of the ultrasonic waves generated by a quartz crystal having  
thickness of 5.5 mm.  
Given y= 80 GPa, p = 2650 kg/m3  
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Q.2 Attempt the following  
a) Explain theory of Newton's rings for reflected light.  
b) Light of wavelength 5500 A falls normally on a thin wedge shaped film of R.L 1.4 forming  
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fringes that are 2.5 mm apart. Find the angle of wedge.  
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OR  
Q.2 Attcmpt the following  
a) Explain the principle and working of He-Ne gas laser  
b) The numerical aperture of an optical fiber is 0.5 and Core refractive index is 1.54. Find the  
rcfractive index of the cladding.  
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Q.3 Attempt the following.  
a) Explain the principle and working of Bainbridgc mass spectrograph.  
b) What is Uncertainty principle? Using this principle prove that electron cannot exist in the  
nucleus.  
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QA Attempt the following.  
a) State and prove Mosley's law. What is its importance?  
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h) Silver has FCC structure and its atomic radius is 1.414 A. Find the interplaner spacing for  
200) planes.  
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Q.5 Attempt the following .  
.a) What is Hysteresis Curve? Explain retentivity, coercivity. Explain B-H curve on the basis of  
domain theory.  
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b) What is Meissner effect and effect of external magnetic field on superconducting state of  
material?  
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At 6 K, critical field is 5 x IojNm. Calculate transition temperature when critieal field is 2 x  
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0" Aim at 0 K.  
QJ, Att('mpt any two of til(' following.  
a) What is Hall effect? Derive an expression for Hall Coefficient and mobility of charge  
carners.  
h) What is electric polarization? Explain with diagrams different types of polarizations III  
dielectric  
c) Derive an expression for electromagnetic wave in free space. Find the value of velocity of  
light in free space.  
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*****  
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