BSc Physics SEM V 2016 17 2016-17 Physics IV Electrodynamics Question Paper - Mumbai University | munotes

Questions asked in this paper

• (2) Figures to the right indicate full marks

1. Q1 (a) Attempt any one of the following: Explain the term electric potential. Using fundamental theorem for gradient 10 the relation E = —V V , hence write comments on the potential Check if the following equation can represent electrostatic field
   • (i) A point charge q is held at a distance 'd' above an infinite grounded 10 conducting plane. Using method of image obtain the.expression for induced charge on the plane, the force acting on charge 'q' and the energy of the Attempt any one of the following:
   • (i) Find electric field outside a uniformly charged solid sphere of radius R 5 and having total charge
   • (ii) Find the potential inside and outside a spherical shell of radius R which 5 carries a uniform surface charge. Set the reference point at oo
2. Q2 (a) Attempt any one of the following:
   • (i) Obtain an expression for potential due to polarized object in terms 19 bound charge density and volume bound charge
   • (i) Using Ampere's circuital law for an infinite solenoid carrying a steady current 10 show that the magnetic field is parallel to the axis of the solenoid. Obtain the expression for magnetic field inside and outside the solenoid. Express the field in vector form
   • (b) Attempt any one of the following: (@) Obtain Gauss law in polarized dielectric
   • (ii) Define energy density for dielectric system. A uniform electric field 5 exist in a linear homogeneous dielectric (dielectric constant 5) Find the energy density stored in the dielectric
3. Q3 (a) Attempt any one of the following:
   • (ii) What is meant by magnetization? Show, using an expression for 10 magnetostatic vector potential, that the magnetization of a medium gives rise to a volume current density and a surface current
   • (b) Attempt any one of the following: Obtain an expression for Ampere's law in presence of magnetic materials. 5
   • (i) A long copper rod of radius R carries a uniformly distributed free current 5
4. Q1 inside the rod & . 4. (a) Attempt any one of the following: () A plane electromagnetic wave is incident normally on the interface oftwo 10 3 non-conducting media. Write expressions for the incident, reflected and transmitted fields. Apply suitable boundary conditions and obtain reflection Q coefficient (R) and transmission coefficient (T)
   • (ii) State and prove Poynting theorem. Compare its differential version with 10
   • (b) Attempt any one of the following: Obtain electromagnetic wave equations in free space from maxwell's 5 equations and show that the velocity of electromagnetic waves in free space equal to velocity of light
   • (ii) Write down the Maxwell's equations for free space. Show that Maxwell's equations already include the principle of conservation of charge
5. Q5 (a) Attempt any one of the following: Show that for electrostatic field curlE=0. 4
   • (ii) An infinite plane carries a uniform surface charge find the electric field 4 just above the plane
   • (b) Attempt any one of the following:
   • (ii) Find the electric susceptibility and pennittivity of diamond (Given: dielectric 4 constant of dimond = 5.7 and, =
   • (c) Attempt any one of the following:
   • (i) Magnetic susceptibility of a linear medium is If auxiliary field 4 is applied along the z-axis, find the magnetization M and
   • (ii) Find the total energy required to set up a uniform magnetic field of 2.0 4 Tesla in a cube of 20cm sides
   • (d) Attempt any one of the following: () The maximum value of magnetic field in a plane electromagnetic wave is 3 0.003T, find the maximum value of electric field associated with this wave Also find the magnitude of Poynting vector for the same wave
   • (i) Obtain an equation of continuity for electrodynamics. 3

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