PREVIOUS PHYSICS QUESTIONS:
Set No. 1
I B.Tech Semester Regular Examinations, June 2009
APPLIED PHYSICS
(Common to EEE, ECE,CSE,EIE,BME,IT,E.CONT.E,CSS,ETM,ECC AND
ICE)
Answer any FIVE Questions
1. (a) Explain the formation of an ionic crystal, with a suitable example.
(b) Derive an expression for the cohesive energy of an ionic crystal. [6+10]
2. (a) Explain the properties of matter waves.
(b) Describe GP Thomson’s experiment to verify the wave nature of matter.
[6+10]
3. (a) Explain the terms
i. mean free path
ii. relaxation time
iii. drift velocity and
iv. mobility of an electron in a metal.
(b) Discuss the various drawbacks of classical free electron theory of metals and
explain the assumptions made in quantum theory to overcome the drawbacks.
[8+8]
4. (a) What are the sources of permanent dipole moment in magnetic materials?
(b) Explain the hysteresis loop observed in Ferro-magnetic materials.
(c) Write notes on Ferro-electricity. [6+6+4]
5. (a) What is superconductivity? Explain the effect of temperature and strength of
magnetic field on a superconducting material.
(b) Write a note on Meissner effect relating to superconductivity.
(c) The transition temperature for lead is 8.7 K. The maximum critical field for
the material is 6 × 105 A/m. If lead is to be used as a superconductor at 3 ×
106 A/m, find the corresponding temperature. [6+6+4]
6. (a) Explain the characteristics of a LASER.
(b) Describe the construction and working of GaAs semiconductor laser.
(c) Write any four applications of laser. [4+8+4]
7. (a) What are the differences between photography and holography?
(b) What is the basic principle of holography? Explain.
(c) Write the applications of holography. [4+6+6]
8. (a) Write a detailed note on nanoscience and nanotechnology.
(b) Write the important applications of nanomaterials in medicine. [10+6]
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Code No: R07A1BS05 Set No. 2
I B.Tech Semester Regular Examinations, June 2009
APPLIED PHYSICs
Answer any FIVE Questions
⋆ ⋆ ⋆ ⋆ ⋆
1. (a) Explain the formation of an ionic crystal, with a suitable example.
(b) Derive an expression for the cohesive energy of an ionic crystal. [6+10]
2. (a) Discuss how Planck introduced the idea of quantum of energy, to explain the
radiation of a black body.
(b) Write short notes on:
i. de Broglie hypothesis and
ii. Electron diffraction. [8+8]
3. (a) Derive an expression for conductivity of a metal on the basis of classical free
electron theory.
(b) Write the draw backs of classical free electron theory.
(c) The relaxation time of electrons in a conductor at 300 K is equal to 1.99 ×
10−14 sec. Determine the electrical conductivity of that conductor. [Concen-
tration of electrons = 8.5 × 1028 per m3] [8+4+4]
4. (a) Explain the following:
i. Electric Polarization
ii. Polarization vector
iii. Electric displacement and
iv. Polarizability.
(b) What is local field in a dielectric material? Derive an expression for it by
Lorentz method. [6+10]
5. (a) Explain Hall effect in semiconductors, and its importance.
(b) In a Hall experiment, a current of 25 A is passed through a long foil of silver
which is 0.1 mm thick and 3.0 cm wide. If the magnetic field of flux density
0.14 wb/m2 is applied perpendicular to the foil, calculate the Hall voltage
developed and estimate the mobility of electrons in silver. The conductivity
of silver is 6.8 × 107 ohm−1
m−1 and the Hall coefficient is -8.4 × 10−11
m3/coul. [10+6]
6. (a) Explain the characteristics of a LASER.
(b) Describe the construction and working of GaAs semiconductor laser.
(c) Write any four applications of laser. [4+8+4]
7. (a) What are important features of optical fibers?
(b) Describe the communication process using optical fibers.
(c) Write the uses of fiber optics in different fields. [4+6+6]
8. (a) What are nanomaterials? Explain.
(b) Describe the various types of carbon nanotubes.
(c) Explain the fabrication of carbon nanotubes. [4+6+6]
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Code No: R07A1BS05 Set No. 3
I B.Tech Semester Regular Examinations, June 2009
APPLIED PHYSICS
(Common to EEE, ECE,CSE,EIE,BME,IT,E.CONT.E,CSS,ETM,ECC AND
ICE)
Answer any FIVE Questions
⋆ ⋆ ⋆ ⋆ ⋆
1. (a) Explain the forces between the two interacting atoms when they are brought
nearer to form a molecule.
(b) Derive the expression for the equilibrium spacing of two atoms for which the
potential energy is minimum. [6+10]
2. (a) Write short notes on:
i. Planck’s quantum theory and
ii. Heisenberg’s uncertainty principle.
(b) Describe G.P.Thomson’s experiment in support of de Broglie’s hypothesis.
(c) Find the wavelength associated with an electron rose to a potential 1600 V.
[6+6+4]
3. (a) Explain the classical free electron theory of metals.
(b) Derive an expression for conductivity of a metal on the basis of classical free
electron theory. [8+8]
4. (a) Explain the origin of magnetic moment. Find the magnetic dipole moments
due to orbital and spin motions of an electron.
(b) How materials are classified as dia-magnetic, para-magnetic and ferro-magnetic?
Explain. [8+8]
5. (a) Derive an expression for the carrier concentration of an intrinsic semiconduc-
tor.
(b) Find the resistance of an intrinsic germanium rod 1.0 cm long, 1.0 mm wide
and 1.0 mm thick at 300 K. The intrinsic carrier density is 2.5 × 1019 per m3
at 300 K, and the mobility of electrons and holes are 0.39 and 0.19 m2 V−1
s−1 respectively. [10+6]
6. (a) Explain the need of a cavity resonator in a laser.
(b) With the help of a suitable diagram describe the construction and working of
a semiconductor laser.
(c) Write any four applications of laser. [4+8+4]
7. (a) What are important features of optical fibers?
(b) Describe the communication process using optical fibers.
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Code No: R07A1BS05 Set No. 3
(c) Write the uses of fiber optics in different fields. [4+6+6]
8. (a) Write a detailed note on nanoscience.
(b) Why nanomaterials exhibit different properties? Explain. [6+10]
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Code No: R07A1BS05 Set No. 4
I B.Tech Semester Regular Examinations, June 2009
APPLIED PHYSICS
(Common to EEE, ECE,CSE,EIE,BME,IT,E.CONT.E,CSS,ETM,ECC AN
Answer any FIVE Questions
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1. (a) Show that FCC is the most closely packed out of the three cubic structures
by calculating the packing factors.
(b) Describe the 3-dimensional Bravais lattices in combination with crystal sys-
tems. [6+10]
2. (a) Show that the wavelength (λ) of an electron having mass (m) and kinetic
energy (E) is given by λ= h
p2mE .
(b) Write a detailed note on Heisenberg’s uncertainty principle.
(c) Calculate the de Broglie wavelength of neutron whose kinetic energy is two
times the rest mass of electron. [Mass of neutron = 1.676 × 10−
27 Kg, Mass
of electron = 9.1 × 10−
31 Kg]. [6+6+4]
3. (a) Explain the classical free electron theory of metals.
(b) Explain the terms
i. drift velocity and
ii. mobility of electrons in a metal.
(c) Write the drawbacks of classical free electron theory of metals. [6+6+4]
4. (a) Describe the phenomenon of electronic polarization and obtain an expression
for electronic polarizability.
(b) The dielectric constant of helium at 0 0C is 1.000074. The density of atoms is
2.7 × 1025 per m3. Calculate the dipole moment induced in each atom when
the gas is in an electric field of 3 ×104 V/m. [permittivity of free space = 8.85
×10−
12 F/m] [10+6]
5. (a) Write a note on intrinsic semiconductors.
(b) Derive an expression for the number of electrons per unit volume in the con-
duction band of an intrinsic semiconductor. [6+10]
6. (a) Explain the purpose of an active medium in a gas laser.
(b) With the help of a suitable diagram, explain the principle, construction and
working of a semi conductor laser.
(c) Calculate the wavelength of emitted radiation from a homo-junction semicon-
ductor diode laser, which has a band gap of 1.44 eV. [4+8+4]
7. (a) Define the relative refractive index difference of an optical fiber. How it is
related to numerical aperture?
(b) Draw the block diagram of an optical fiber communication system and explain
the function of each block. [6+10]
8. (a) Write a detailed note on nanoscience.
(b) Why nanomaterials exhibit different properties? Explain. [6+10]
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- Note:In the above previous question papers few questions are being removed from the syllabus[2010-2011].
- Any suggestions for improvement in the utility of the above information will be very much appreciated..
