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D 31828 (Pages : 2) Name

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THIRD SEMESTER (CBCSS—UG) DEGREE EXAMINATION
NOVEMBER 2022

Physics/Applied Physics
PHY 3B 03/APH 3B 03—ELECTRODYNAMICS—I
(2019 Admission onwards)

Two Hours Maximum : 60 Marks

The symbols used in question paper have their usual meanings.
Section A (Short Answer Type)

Answer all questions in two or three sentences.
Each correct answer carries amaximum of 2 marks.

What do you mean by the Laplacian of a scalar ? Is it a scalar or a vector ?

Write down an expression for the electric field due to a volume charge. Discuss the terms involved.
Give Poisson’s equation and explain the terms involved.

How is the work and energy related in electrostatics ? Is the electrostatic force conservative ?

Write down the expression for the torque experienced by a dipole in uniform electric field. What is
the effect of the torque ?

Write down the relation connecting permittivity and susceptibility in linear dielectrics. Explain
the terms involved. What is the susceptibility of vacuum ?

Check whether the following statements are true or false : (i) Magnetic forces can alter the direction
in which a charged particle moves ; and (ii) Magnetic forces can speed up a charged particle.

Write and explain the expressions for the divergence and curl of B in magnetostatics.
Explain the equation of continuity.

What is the relation connecting magnetic flux density B and magnetic vector potential A ? What is
the divergence of A ?

When will you say that a medium is magnetically polarized ? Discuss the magnetic polarization in
diamagnets.

Explain the temperature-driven phase transitions in ferromagnetic materials.
(Ceiling 20)

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