Andhra University BSc Physics

PHYSICS - Paper III - Electromagnetics & Electronics (for Mathematics students)

1.Electrostatics : Coulomb's law. MKSA system of units - charge distributions - discrete and continuous. Electric field. The scalar potential. Field and potential due to a dipole : due to N discrete point changes : due to continuous change distribution. Potential of a long charged wire. Potential of a uniforily charged circular disc. Gauss law (integral and differential forms). Applications : Electric field due to an infinite sheet of charge, field due to a spherical distribution of charge at points within and outside the sphere.

2. Conductors : Conductor as an equipotential surface. Field near the surface of a conductor. Field near a charged conducting planed. Field near a conducting spherical shell, capacitance of a parallel plate capacitor, of a concentric spherical shell and of a sphere. Electrostatic energy of a charged capacitor.

3. Dielectrics : Origin of polarisation, Polarisation, charge - density Electric field due to polarisation - Relation between D.E. and P. Dielectric constant and Electric susceptibility. Gauss law in the presence of dielectrics. Boundary conditions on D and E. Capacitance of a capacitor with a dielectric. Energy density within a dielectric. Dielectric breakdown.

4. Steady Currents : Current density. Equation of continuity, surface current density, Electrical conductivity and Ohw's law, EMP, Energy dissipation, reciprocity theorem, Kirchhoff's laws. Mesh and Node analysis. Superposition principle. Thevenin and morton theorems.

5. Magnetostatics : Definition of B - Biotsavart law - Divergence of B. Magnetic flux - the Surface integral of B. B due to a long straight current. Ampere's law (integral and differential forms). B along the axis of a circular loop carrying current. Field due to Helmholtz coils. Force on a current element due to a field B. Force between two parallel wires carrying currents. Definition of Ampere. Torque on a current loop. Moving coil galvanometre. The solenoid and the toroid. Motion of a charged particle in a uniform magnetic field. Helical path, focussing action and Hall effect. Motion of charged particles in electric and magnetic fields.

6. Electromagnetic Induction: Taraday's law (integral and diff erential forms), Lenz's law, expression for induced EMF Time-varying magnetic fields - Betatron - Self induction. Self inductance of a long straight wire and a sole.noid. Mutual induction. Coefficient of coupling. Inductance and magnetic energy.

7. Magnetic Fields in Matter : Para, dia and ferro magnetic substances, Magnetisation, Relation between 8, M and H. Definition of H, Magnetic susceptibility, Hysterisis. B-H curve, Y Ferromagnetism. Magnetic domains, Boundary conditions on B and H. The magnetic circuit.

8. Varying and Alternating Currents : Circuit with L and R, charging and discharging of a capacitor through R, Discharge of a capacitor through L. Series LCR circuit. Sinusoidal voltage applied to (i) a resistance (ii) and inductrance andd (iii)) across a capacitance. Phasors and phase diagrams. Use of complex numbers. Reactance and impedance. Inductive and capacitive reactances - power factor -LCR circuits - Series resonant circuit - Q factor - Parallel resonant circuits - Generators, Motors and Transformers (Principles only).

9. Maxwell's Equations : Review of basic laws of Electricity and Magnetism. Displacement current. Ampere's law in general form. Maxwell's equations. Plan EM waves, Transverse nature of EM waves, Energy density, energy flow (poynting vector).

10. Electronics : Diodes : Junction diode - Volt ampere characteristics. Half wave rectifier, Full wave rectifier and Bridge rectifier - Ripple factor - Capacitive and inductive filters. (Qualitative). Zener diode, its characteristics. Transistors, working of a transistor, currents in a transistor, DC Alpha, CB, CC and CE configurations, characteristics of CE configuration. CE amplifier, biasing, voltage divider bias, single stage R.C. couple amplifier - graphical analysis only. Oscillators : Positive feedback amplifier as oscillator - Barkhausen criterion, phase shift oscillator. Modulation and detection : Amplitude modulation. Frequency modulation -Demodulation using diodes - Elementary principles of radio transmission and reception.

Digital Electronics : Binary arithmatics, and or, not gates using discrete components. Truth tables - NAND, NOR and ZOR gares half adder and full adder. De Morgan's theorems - RS Flipflot counters registers and memory elements.

Textbooks Recommended
1. Electricity and Magnetism by Mahajan and Rangawala (TMH)
2. Basic Electronics and Linear Circuits by Bhargawa, Kulashrashta and Gupta (TT 11, Chandigarh)
3. Digital principles and applications by Malvino and Leach (TMN)

Books Recommended for Supplementary Reading
1. Physics II by Halliday and Resnick (Siley Eastern)
2. Electricity and Magnetism by D.N. Vasudeve (S Chand)
3. Electronic Fundamentals and applications by John D. Ryder (DHI)