FIRST ASSESSMENTII sem. B.E. ECE (CD) BRANCH 14 February 2013Time: 50 min. ( Max. Mark: 25)PH8252 - PHYSICS FOR ELECTRONICS ENGINEERINGPart - A Answer ALL Questions (5 × 2 = 10 Mark )

(1) Which properties of metals are not described adequately by Drude’smodel?

(2) What is the applied electric field that will impose a drift velocity equal to0.1 % of the thermal speed (at room temperature) of conduction electronsin copper?

(3) Calculate the energy (in units of KT ) relative to the Fermi energy forwhich the Fermi function equals 5%.

(4) Calculate the Fermi energy at 0 k for a monovalent gold (Au). The densityof Au is 19.3 g cm−3 and the atomic mass is 196.97 amu.

(5) Why does a completely filled band not contribute the conductivity of asolid?

Part - B ( 15 Mark )(6) (a) Deduce a mathematical expression for electrical conductivity and

thermal conductivity of a conducting material and hence obtain theexpression for Wiedemann - Franz law.

(OR)(b) Obtain an expression for the energy of an electron in an infinitely

deep potential well having one dimension. Discuss its probability oflocation inside the well.

FIRST ASSESSMENTII sem. B.E. ECE (CD) BRANCH 14 February 2013Time: 50 min. ( Max. Mark: 25)PH8252 - PHYSICS FOR ELECTRONICS ENGINEERINGPart - A Answer ALL Questions (5 × 2 = 10 Mark )

(1) Which properties of metals are not described adequately by Drude’smodel?

(2) What is the applied electric field that will impose a drift velocity equal to0.1 % of the thermal speed (at room temperature) of conduction electronsin copper?

(3) Calculate the energy (in units of KT ) relative to the Fermi energy forwhich the Fermi function equals 5%.

(4) Calculate the Fermi energy at 0 k for a monovalent gold (Au). The densityof Au is 19.3 g cm−3 and the atomic mass is 196.97 amu.

(5) Why does a completely filled band not contribute the conductivity of asolid?

Part - B ( 15 Mark )(6) (a) Deduce a mathematical expression for electrical conductivity and

thermal conductivity of a conducting material and hence obtain theexpression for Wiedemann - Franz law.

(OR)(b) Obtain an expression for the energy of an electron in an infinitely

deep potential well having one dimension. Discuss its probability oflocation inside the well.

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