BSC Part II Semester III Physics Exam (AD-1823) PDF

AD–1823 B.Sc. Part—II Semester—III Examination PHYSICS Time : Three Hours] [Maximum Marks :...

AD–1823 B.Sc. Part—II Semester—III Examination PHYSICS Time : Three Hours] [Maximum Marks : 80 Note :— (1) All questions are compulsory. (2) Draw neat labelled diagrams wherever necessary. 1. 1 3 (A) Fill in the blanks : 4 (i) The line integral of conservative field over closed path is _____. (ii) In transistor base region is always _____ doped. 3 41 (iii) Oceanic crust is mainly made of _____ rock. (iv) _____ is cloud responsible for precipitation of rain. ½×4=2 (B) Choose the correct alternatives : r (i) Divergence of vector field F is represented by : r r (a) ∇ · F (b) ∇ × F r r (c) F × ∇ (d) ∇ × (∇ × F) 1 3 4 (ii) Electric flux is which of these quantity ? (a) Scaler (b) Vector (c) Pseudo power (d) None of these r (iii) The equation ∇ · B = 0 represents : (a) Faraday’s Law (b) Ampere’s Law (c) Gauss Law in Magnetostatics (d) Gauss Law in Electrostatics (iv) Ozone layer located in : (a) Troposphere (b) Stratosphere (c) Thermosphere (d) Exosphere ½×4=2 (C) Answer in one sentence each : (i) Define a term Seismology. 1 3 (ii) What is intrinsic semiconductor ? 1 3 4 (iii) Define Transconductance in Mathematical form. 4 (iv) Define Forbidden energy band gap. 1×4=4 LT—28402 1 (Contd.)  UNIT—I 2. (A) State and prove Stoke’s theorem. 6 (B) Define divergent of vector and give its physical significance. 4 (C) Explain surface integral. 2 OR r 3. (P) Derive an expression for work done on charged particle (q) in Electrostatic field E. 5 3 (Q) Derive an expression for magnetic induction along the axis of Toroid by using Amperes 1 4 law. (R) Explain Lorentz Force equation. 5 2 UNIT—II 3 4. (A) State and prove Poynting theorem. 6 41 (B) Derive an expression : r r ∂B ∇×E=− 4 ∂t (C) State and explain Lenz’s Law of electromagnetic induction. 2 OR 5. (P) Derive an expression for electromagnetic wave in vacuum. 6 r 13 (Q) Derive Maxwell equa tion ∇ · D = ρ. Give its physical significance. 6 6. 4 UNIT—III (A) Classify the solids into conductor, semiconductor and insulator on the basis of energy band gap. 4 (B) Explain construction and working of LED and explain its advantages and application. 8 OR 7. (P) Explain VI characteristics of PN-junction diode in forward and reverse bias. 6 (Q) Describe current in semiconductor. 4 (R) What is doping in semiconductor ? 2 UNIT—IV 8. (A) Draw circuit diagram of CE amplifier and explain its input and output characteristics. 6 (B) Explain construction and working of PNP transistor. 6 OR 9. 1 3 1 3 (P) Explain OP-AMP as an inverting amplifier and hence derive expression for its voltage 4 gain. 4 5 (Q) Explain OP-AMP as an integrator with suitable diagram. 5 (R) Find voltage gain for the inverting amplifier for Ri = 10 kΩ and RF = 1 MΩ. 2 LT—28402 2 (Contd.)  UNIT—V 10. (A) Derive Lorentz transformation equations. 6 (B) Derive energy mass equivalence relation. 6 OR 11. (P) Define time dilation, obtain an expression for it. 4 (Q) Obtain an expression for relativistic mass. 5 1 3 (R) What will be length of meterscale moving with velocity 0.9c ? 3 4 UNIT—VI 12. (A) Explain internal structure of Earth. 6 3 (B) What is earthquake ? Explain its type based on origin, depth of focus and intensity 41 scale. 6 OR 13. (P) How to determine exact position of epicenter ? 3 (Q) Define seismic wave. Explain its types. 5 (R) Explain importance of ozone layer. 3 (S) Define Focus of Earthquake. 1 1 3 4 1 3 1 3 4 4 LT—28402 3 25