7/24/2019 I AAT Question Bank

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Bapatla Engineering College:: Bapatla(Autonomous)

Department of PhysicsQuestion Bank, Engineering Physics-II,Unit-I

I. Each question carries 1 mark.1. What is the basic assumption of quantum free electron theory?

2. Define Fermi level E F3. ive relation bet!een E n an" #?4. ive the Fermi$Dirac "istribution function f%E&?5. ive the mathematical form for effective mass of electron?'. ive ener(y (ap E ( values for silicon an" (ermanium?). What is *loch theorem?+. Define reverse saturation current?,. Define rela-ation time an" collision time?1 . What is the /la! of mass action0 an" (ive its importance?

II. Each question carries 6 marks.1. What are the assumptions of classical free electron theory an" Write its merits.

What are the assumptions of quantum free electron theory?2. Discuss the formation of allo!e" an" forbi""en ener(y ban"s on the basis of roni($ enny mo"el.3. E-plain the effective mass of an electron an" e-plain the concept of hole.

. Derive the e-pression for carrier concentration in 4$type semicon"uctors.5. !rite the construction an" !or#in( of a p$n 6unction "io"e an" e-plain its 7$8 characteristics.'. E-plain about Density of states. Write a short note on Drift an" Diffusion.

Note 9 ::; consists of four 1< %:ny four from bit ban#& an" one '< =uestions %:ny one from bit ban#&.;he total mar#s of ::; is 1