BSc Physics SEM V 2018 19 2018-19 Physics Electrodynamics Question Paper - Mumbai University | munotes

Questions asked in this paper

• (2) Figures to the right indicate full marks

1. Q3 Electronic charge = 1.6 x
2. Q1 Attempt any
   • (a) State and prove First and Second Uniqueness theorems. 10
   • (b) Determine the curl of electric field due to.a point charge in free space. 10 Show that the electrostatic field is obtained as F = —VV
   • (c) Derive the Gauss’s law in integral form. 10 Find the electric field in the three regions: (i) r< a, a<r<b, (iii) r>b
   • (a) an expression for energy stored in a linear homogeneous dielectric 10
   • (b) Derive the Ampere’s law using Biot-Savart’s law. 10 Compare Electrostatics and Magnetostatics
   • (c) Derive an expression for potential due to a polarized object in terms of bound 10 charges. Show that o, = = P
3. Q3 Attempt any T wo:
   • (a) State the Maxwell’s equations before applying correction to it. Explain the need 10 to correct these equations. How did Maxwell resolve this difficulty?
   • (b) Derive an expression for vector potential due to magnetized object in terms of 10 An infinitely long circular cylinder carries a uniform magnetization M parallel to its axis. Find the magnetic field due to M inside and outside the cylinder There is no free current anywhere
   • (c) Obtain the boundary conditions for the fields: Electric field E, Electric 10 Displacement D, Magnetic field B and auxiliary field H
4. Q4 Attempt any
   • (a) State and prove Poynting’s theorem. Obtain the differential version of Poynting 10
   • (b) Write the Maxwell’s equations for a region with no free charges and free 10 currents. Obtain the wave equation from Maxwell’s equation. Show that for plane wave solutions the electric field, magnetic field and the direction of propagation are mutually perpendicular
   • (c) In case of plane monochromatic wave show that the contribution towards the 10 energy density from magnetic and electric fields are equal. Obtain the expression for average values for energy density, Poynting vector, and momentum density in case of plane monochromatic wave
5. Q5 Attempt any Four:
   • (i) Determine if any of the following vectors can be electrostatic field: 05
   • (ii) = + + If the potential is a function of only position vector r, V(r), then solve 05 meter. Calculate the magnetic field inside and outside the solenoid
   • (iv) atom with the Bohr radius of half an angstrom is situated 05 between two metal plates | mm apart, which are connected to opposite terminals of a 500V battery. What fraction of the atomic radius does the separation distance‘d’ amount to, roughly?
   • (v) The magnetic susceptibility of a linear sample of Tungsten is 05 7.8 If auxiliary field (H) of 50,000 Ampere.turns/m is applied along the z-axis, find the magnetization M and the magnetic field B in
   • (vi) A parallel plate capacitor is immersed in a sea water with permittivity 05 = permeability = and resistivity p = 0.232.m. The capacitor is driven by the voltage and frequency 4x What is the ratio of conduction current to displacement
   • (vii) wave in empty space has amplitude of electric field 05 300V/m find the value of amplitude of magnetic field(c=3 x An electromagnetic wave is incident normally on the surface of glass 05 from air, find the reflection coefficient. Given (n=1.5)

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