**PH8252 Question Bank Physics for Information Science**

PH8252 Question Bank Physics for Information Science Regulation 2017 Anna University free download. Physics for Information Science PH8252 Question Bank pdf free download.

Give the postulates of free electron theory. Derive an expression for electrical conductivity of a metal by using classical free electron theory.

(13)

BTL5

Evaluating

2.

i) Explain the assumptions of classical free electron theory, its merits and demerits. (8)

BTL2

Understanding

ii) Calculate the electrical and thermal conductivities for a metal with a relaxation time 10-14 second at 300 K. Also calculate Lorentz number using the above result. (Density of electrons = 6×1028 m-3). (5)

BTL5

Evaluating

3 PH8252 Question Bank Physics for Information Science

(i) Define thermal conductivity and hence deduce an expression for the same. (10)

Elaborate the mathematical expression for electrical conductivity and thermal conductivity of a conducting material and hence obtain Weidemann-Franz law (13)

BTL1

Remembering

5.

State and prove Wiedemann-Franz law. Why does the Lorentz number determined experimentally does not agree with the value calculated from the classical theory? (13)

BTL2

Understanding

6.

Determine the expression for thermal conductivity in metals. (13)

BTL5

Evaluating

7.

Obtain Wiedemann Franz law using the expressions of electrical and thermal conductivity and find the expression of Lorentz number. (13)

BTL3

Applying

8. PH8252 Question Bank Physics for Information Science

(i)Write an expression for the Fermi energy distribution function F (E) and discuss its behaviour with change in temperature. Plot F (E) versus E for T= 0 K, and T > 0 K. (10)

BTL2

Understanding

ii) Use the Fermi distribution function to obtain the value of F (E) for the level just 0.01eV above the Fermi level at 200 K. (3)

BTL5

Evaluating

9.

Discuss Fermi distribution function and explain its variation with temperature. (13)

BTL2

Understanding PH8252 Question Bank Physics for Information Science

10.

Define Fermi energy. Obtain a general expression for the Fermi energy of electrons in solids at zero degree Kelvin. Show that at the same temperature, the average energy of the electron is (3/5) th of Fermi energy. (13)

BTL5

Evaluating

11.

Obtain an expression for the density of energy states for a metal.

Subject Name | Physics for Information Science |

Subject Code | PH8252 |

Regulation | 2017 |

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