### Engineering Physics – I Part A and B questions bank

Sub. Name : Engineering Physics – I
UNIT – 1 ULTRASONICS AND ITS APPLICATIONS
PART – A ( 2 Marks)
1. How are sound waves classified?
2. Mention the properties of ultrasonics.
3 . What is meant by Piezo electric effect?
4. What are the methods used for the detection of ultrasonics?
5 . What is meant by Cavitation?
6. What is acoustic grating?
7. Mention some of the industrial applications of ultrasonics?
8.. What is meant by SONAR?
9. State Doppler Effect.
10. Mention some of the medical applications of ultrasonics.
11 Name different scanning methods used in ultrasonics.
12. What is called Magnetostriction effect?
13 A quartz crystal of thickness 0.001m vibrates in its frequency.
Calculate its frequency of oscillation.
Given that E=7.9 X1010 N/m2 and ρ =2650 kg/m3 for quartz crystal.
14. An ultrasonic interferometer is used to measure the velocity of
ultrasonic waves in sea water.
If the distance between two consecutive antinodes is 0.55 mm., then
Compute the velocity of the waves in the sea water.
The frequency of the crystal is 1.5 MHz.
15. Find the depth of a submerged submarine if an ultrasonic wave is
received after 0.33 sec from the time of transmission.
Given that the velocity of ultrasonic waves in sea water =1440 m/s
PART – B ( 16 Marks)
1. What is Magnetostriction effect ? Explain how it can be applied for the
production of ultrasonics using magnetostriction oscillator ( 4 + 12)
2. What is Inverse-Piezo electric effect? Explain with neat sketch, the
construction and production of ultrasonic waves using Piezo electric
oscillator. ( 4 + 12)
3 a) Explain the determination of velocity of ultrasonics using an acoustical
grating. (10 )
b) Explain in detail, how SONAR is employed to locate the object (6)
4 a) Draw a schematic diagram of a ultrasonic flaw detector and explain its
action (6)
b) Explain about three ultrasonic scanning methods with necessary display
diagrams.
(10)
UNIT – II LASER AND ITS APPLICATIONS
PART – A ( 2 Marks)
1. What are the characteristics of laser?
2.. Distinguish between spontaneous and stimulated emission?
3. What is meant by population inversion?
4. What are different methods of pumping?
5. What are the conditions required for laser action?
6. Define active medium and active centre.
7. What is meant by an optical resonator?
8. What are the industrial applications of laser?
9. What are the differences between photography and holography?
10. What are the applications of laser in medical field?
11. What are the types of laser?
12. For InP laser diode, the wavelength of light emission is 1.55µm.
What is its band gap in eV?
13. Calculate the wavelength of emission of GaAs semiconductor laser whose
bandgap energy is 1.44 eV.
14. Calculate how many photons are emitted in a minute in a He-Ne laser
source, which emits light at a wavelength of 6328A0.The output power of this
source is 3mW.
15. What is the ratio of the stimulated emission to spontaneous emission at a
temperature of 280oC for sodium D-line?
PART – B ( 16 MARKS)
1. a) What is the principle of spontaneous and stimulated emission? (4)
b) Derive an expression for Einstein's coefficient of stimulated and
spontaneous emission(8)
c) What is the principle of laser action? (4)
2. a) Explain about the different modes of vibrations in CO2 laser. (4)
b) Describe the construction and working of CO2 laser using energy level
diagram (12)
3. a) Discuss with theory, the construction and working of Homogeneous
semi conductor laser (8)
b) Describe the construction and reconstruction of a hologram (8)
4. a) Explain the construction and working of He-Ne Laser (8)
b) Describe the construction and working of Nd-YAG laser (8)
UNIT – III FIBRE OPTICS AND ITS APPLICATIONS
PART – A ( 2 Marks)
1. What is meant by Total Internal Reflection?
2. What are the conditions to be satisfied for total internal reflection?
3. Define acceptance angle and numerical aperture.
4. Distinguish between step index and graded index fibres.
5. What are the losses in optical fibres?
6. Mention any two fiber optic sources?
7. What is meant by photo detector?
8. What are the types of sensors used in the fiber optics?
9. What is called medical endoscope?
communication.
11. Mention some of the medical applications of optical fibres.
12. Mention some of the engineering applications of optical fibres.
13. The refractive indices of core and cladding materials of an optical fibre are
1.54 and 1.5 respectively. Calculate the numerical aperture of the optical
fiber
14. Estimate NA when core refractive index is 1.48, relative refractive index
is 2 %. Also calculate the critical angle.
15. A fibre has a diameter of 6µm and its core refractive index is 1.47 and for
How many modes can propagate into the fibre if the wavelength of the laser
source is 1.5 µm.
PART – B ( 16 MARKS)
1. a) Derive an expression for Numerical Aperture and angle of acceptance of a
fibre in terms of refractive indices of the core and cladding (10)
b) Describe the Crucible-Crucible technique for manufacturing an
optical fibre
(6)
2. a) What are different types of optical fibres? (8)
b) Explain about losses in an optical fibre (8)
3. a) Explain with a neat block diagram of fibre optical communication system (8)
b) Explain about LED and Avalanche Photo diode used in fibre optics (8)
4. a) What are different types of optical sensors? Explain the working of any two
sensors
(4+6)
b) Describe the construction and working of a fiber optic endoscope and give
its applications in medicine (6)
UNIT – IV : QUANTUM PHYSICS
PART – A ( 2 Marks)
1. What is a black body?
2. What are the postulates of planks quantum theory?
3. What is meant by matter waves?
4. What is called Compton shift?
5. What is the physical significance of a wave function?
6. Define magnifying power.
7. Define resolving power of a microscope.
8. What is wave function?
9. Mention the applications of electron microscope.
10. Write down the one dimensional schroedinger time independent wave
equation.
11. An electron at rest is accelerated through a potential of 5000 V. Calculate the
de-Broglie wavelength of matter waves associated with it.
12. Find the change in wavelength of an X-ray photon when it is scattered
through an angle of 1350 by a free electron.
13. Calculate the minimum energy of an electron can possess in an infinitely
deep potential well of width 4nm.
14. What is meant by degenerate and non-degenerate states?
15. Differentiate between optical microscope and electron microscope.
1. a) What is meant by black body radiation ? (2)
b) Using quantum theory derive an expression for the average energy emitted
by the black body and deduce Wien's displacement law and Rayleigh –
Jeans law (10 +4)
2. a) Define Compton Effect? (2)
b) Derive an expression for the wavelength of the scattered photon
(Compton Shift)
(14)
3. a) Derive time independent Schroedinger wave equation (8)
b) Solve Schroedinger wave equation for a particle in a one dimensional box
and energy eigen value. (8)
4. a) Derive the equation for Schroedinger time – dependent wave equation (6)
b) Explain about Electron Microscope with a neat diagram (10)
PART – B ( 16 MARKS)
UNIT – V : CRYSTAL PHYSICS
PART – A ( 2 Marks)
1. What are the differences between crystalline and non-crystalline materials?
2. Define unit cell.
3. Define space lattice.
4. Give the relation between the density of the crystal and lattice constant.
5. What are Bravais lattices?
6. Define atomic packing factor.
7. What are Miller indices?
8. What are lattice parameters?
9. Sketch (110) plane and (111) plane for a cubic crystal.
10. Calculate the lattice constant of Fe. Given: density of iron 7.86 kg/cm3,
atomic weight 55.85 and Avagadro's number 6.023 x 1023 atoms /mol
11. Calculate the inter planar distance for (321) plane in simple cubic lattice with
inter atomic spacing equal to 4.12 A0
PART – B ( 16 MARKS)
1. Determine the atomic radius, coordination number and packing factor for BCC
and FCC structures (8+8)
2. a) Describe the structure of HCP Crystal (8)
b) Calculate the axial ratio (c/a) and atomic packing factor for HCP structure.
(8)
3. a) What are Miller Indices? (4)
b) Show that for a cubic lattice, the distance between two successive planes is
given by
d hkl =( h2 +k2 +l2 )1/2
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