ECE225: Material Science E1208Section: Code A Time 50 min.

Roll No. Reg. No. Max.Marks:30

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Q. 1

a) How many effective numbers of atom are present in Base centered cubic unit cell. Also mention their

Positions.

b) Define the Dislocation.

c) Define crystal structure. (2+2+1)

Q. 2 What is the Significance of Crystallographic Directions? Explain with proper example. (5)

Q.3. Calculate the atomic radius in cm for the following

a) BCC metal with ao = 0.3294 nm

b) FCC metal with ao = 4.0862 Ao (5)

Q 4 Explain the Bravais lattice with proper diagram. (5)

Q 5 Determine –

a) Repeat distance, Linear density and packing fraction for [111] direction in FCC structure.

b) Planner density and Packing fraction for (110) Plane

Consider lattice parameter = 0.3 nm. (5+5)

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ECE225: Material Science E1208

Section: Code B Time 50 min.

Roll No. Reg. No. Max.Marks:30

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Q. 1

a) What makes steel considerably harder and stronger than pure iron.

b) Differentiate the interstitial and substitution defect in crystal.

c) What is Kepler’s Conjecture? (2+2+1)

Q. 2 Determine the relationship between atomic radius and lattice parameter for FCC and BCC structures. (5)

Q 3 Calculate the number of vacancies per cm3 expected in copper at 1080°C (just below the melting temperature). The energy for vacancy formation is 20,000 cal mol. (5)

Q 4 Explain the beneficial and deleterious properties of impurity in material with proper example (5)

Q 5. Write Rules of construction of direction and Planes. Draw directions and Planes for the following miller indices [1 3 0] & ( 2 1 2) (5+5)

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ECE225: Material Science E1208

Section: Code C Time 50 min.

Roll No. Reg. No. Max.Marks:30

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Q. 1

a) Define interstitial sites. Write types of interstitial sites also.

b) Differentiate frenkel defect and schottky defect.

c) Define Material Science. (2+2+1)

Q. 2. Calculate planer density and Planer packing fraction for the (010) plane of Simple cubic polonium, which has lattice parameter of 0.334 nm. (5)

Q 3 What is the significant of coordination number? Prove it with the help of example (5)

Q 4 Gold has 5.82×108 vacancies cm3 at equilibrium at 300 K. What fraction of the atomic sites is vacant at 600 K?

(5)Q 5. Write Rules of construction of Planes. Determine miller indices for Plan ( 113 ). (10)

.

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