Download AKTU B-Tech 4th Sem 2016-17 Electrical And Electronics Engineering Material Question Paper

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B.TECH.

THEORY EXAMINATION (SEM–IV) 2016-17

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ELECTRICAL AND ELECTRONICS ENGINEERING MATERIAL

Time: 3 Hours

Max. Marks : 100

Note: Be precise in your answer. In case of numerical problem assume data wherever not provided.

SECTION – A

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10 x 2 = 20

1. Explain the following:
   1. What do you mean by co-ordination number ?
   2. Find the miller indices for a plane when the intercepts along the axes are 2a, 3b and 2c.
   3. What is the difference between crystalline and non-crystalline material?
   4. Explain seebeck effect.

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   5. What is superconductivity? Name some super-conducting material.
   6. Differentiate between drift and diffusion current.
   7. What happen when a p-n junction is biased in forward direction?
   8. Why does a pure semiconductor behave like an insulator at absolute zero?
   9. Give relationship between relative permeability and magnetic susceptibility.

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   10. Draw hysteresis curve for a ferromagnetic material.

SECTION - B

Attempt any five of the following questions:

5 x 10 = 50

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1. 1. Define the following: (i) Unit cell (ii) Space lattice (iii) Atomic packing factor
   2. Explain Bragg's law. How Bragg's equation can be used to determine the lattice parameters. Determine the interplanar distance in a crystal in which a series of planes produce a first order reflection from a copper X-ray tube (? = 1.539Å) at an angle of 22.5°
   3. Explain the "Meissner Effect". Also explain Type-I and II superconductors with examples.
   4. Derive an expression for heat developed in a current carrying conductor. Also explain the factors responsible for it.
   5. Explain in detail p-n junction diode and its VI characteristics.

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   6. Distinguish between insulator, conductors and semiconductor on the basis of band theory. Give the electrical characteristics of n-type and p-type semiconductors.
   7. How do you classify the material as dia, para or ferromagnetic? Explain ferromagnetism in detail.
   8. What is magnetostriction? How many types are possible?

SECTION – C

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Attempt any two of the following questions:

2 x 15 = 30

1. Determine the atomic packing factor of the following:
   1. Simple cubic crystal
   2. Body centered cubic crystal
   3. Face centered cubic crystal.

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2. What is Hall Effect in semiconductor? The resistivity of doped silicon crystal is 9.23 × 10³ Q-m and hall coefficient is 3.84 × 10^-4 m³C^-1. Assuming that the conduction is by a single type of a charge carrier calculate the density and mobility of carrier.
3. 1. Distinguish between soft and hard magnetic materials. Discuss and explain typical B-H curve for soft magnetic material.
   2. Determine the temperature coefficient of resistance of material used in a resistor if the resistance at 25°C is 50 O and at 70°C is 57.2 O.

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