RTU 2016 Question Paper Semester I Engineering Physics I

Total No ol Pages; I
m 1E2003
o
o Tech I Sem. (Main/Back) Exam' Jan' 2016
N 103 Engineering PhYsics-I
II]
F,{ Common to all Branches

Maximum Marks: 80
Time: 3 Hours
Min. Passing Marks: 2zl
Instructions to Candidates :
each unit' All questbns
Attempt any five questions, selecting one question from
Any
,iii'ri,q"it *oris. schematic diagiams iust be shown wherever necessary.
ioti you Trrl missing suitably be assumed antl stated clearly'
Units of quantities used/calculated must be stated clearly'
exatnination'
Use of following supportitxg material is permitted during
2. N}L
I. NIL

interferometer' How may it
Q.l (a) Describe the construction and working of Michelson 'light'l
[6+4=101
be used to measure the wavelength of monochromatic

(b) Newton's rings are observed in reflected light of wavelength 5x10-s cm The
diameteroflOthdarkringis0.5cm'Findradiusofcurvatureoflensandthickness
t6l
of the air film at the ring.

OR
[4+4=8]
Q.l (a) Write short notes on the following -
(i) Anti - reflection coating
(ii) Interferencefilter

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(b) Explain Newton's ring method for determining the wavelength of
monochromatic light. Why is the centre of the ring dark and how can we get a
bright centre. t8l

UNIT.II
Q.2 (a) Describe the construction and working of a Laurent's half shade polarimeter. I I 0]

(b) Calculate the thickness of a half wave & quarter wave plate of quartz for a
wavelength of 5000A'. Here po = 1.553 & ttE = 1.544. t6l

OR

Q.2 (a) What is optical activity? Write the laws of optical activity of optically active
solution. t6l

(b) A retardation plate of thickness 8.56x10-7 m introduces a phase difference in the
path of polarized light of wavelength of 5890A". The principle refractive indices

are U.o = I .658 & p. = t .486. Find the nature of retardation plate. t6t

(c) State and explain law of Malus. 14l

Q.3 (a) Derive an expression for the intensity of diffracted light in fraunhofer's
diffraction due to single slit. t8I

(b) The distance between the first and sixth minima in the diffraction pattem of a
single slit is 0.5mm. The screen is 0.5m away from the slit. If the wavelength of

light used is 5000A", determine the slit width. t8t

[1E2003] Page 2 of 4 Is1460]

OR

Q.3 (a) Explain Rayleigh Criteria of just resolution of two spectlal lines of equal
intensities giving suitable intensity distribution curve. Show how the resolving
power of a plane transmission grating depends on -

(i) No. of ruled lines
(ii) Width of ruled splace. t8l

(b) Show that the intensity of light diffraction from a plane transmission grating is
given by -

r=r"l'L['ilTPl'
fl' \
slnp /
where symbols carry their usual meaning. t8l

UNIT.IV
Q.a (a) Exptain the term bonding in crystals? what are the distinguishing characteristics
of metallic bonding? t8l

(b) What is Hall Effect? Briefly discuss the physical origin of Hall effect. t81

OR

e.4 (a) The resistivity of doped Silicon sample is 8.9x10-3 Om. The Hall coefficient was
measured to be 3.6x10-a m3/C' Assuming single carrier conduction, find the
mobility and density of charge carriers. t8l

(b) Classify the soil as conductor, semiconductor and Insulator according to band
' structure' t8l

[1E2003] Page 3 of4 [51460]

UNIT.V
Q.5 (a) A Spaceship (at rest) of length l00m takes 3ps to pass an observer on earth.
What is its velocity relative to the earth? t8l
(b) Derive an expression for the variation of mass with velocity. t8l

OR

Q.5 (a) Write short notes on relativistic time dilation and examples. l4l
(b) State the postulates of special theory of relativity and deduce the Lorentz
transformation. t8l
(c) What is the total energy of an electron at rest, mass 9.lxl0-3r kg moving with
speed of0.956? t4l

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