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OM SAKTHI

147403/ELECTROMAGNETIC FIELDS

UNIT - II

PART A

1. Define magnetic fluxThe total number of magnetic lines of force is called magnetic flux. Unit -

Weber (Wb)

2. Define magnetic field intensity(H)Magnetic field intensity (H) at any point in the magnetic field is defined as the

force experienced by a unit north pole of one weber strength, when placed at that point.

Unit - N/wb (or) Amp/m (or) AT/m

3. Define magnetic flux density (B)The magnetic flux crossing a unit area in a plane at right angles to the direction of

flux is called magnetic flux density (B). Unit Wb/m2

(or) Tesla

4. Relate magnetic field intensity and magnetic flux densityMagnetic flux density (B) = Permeability () Magnetic field intensity (H)

B =H = H

[ It is the ability with which the current carrying conductor forces the

magnetic flux through the region around it

Absolute

Relative Permeability , for free space , B = H]

5. State Biot-Savart law in vector formIt states that, the differential magnetic field intensity dH produced at a point P

due to differential current element I dL is,

i) Proportional to the product of the current I and the differential length dLii) Proportional to the Sine of the angle () between the element and the line

joining point P to the element

iii) Inversely Proportional to the square of the distance Rbetween point P andthe element

=

= Proportionality constant}

Vector form: dL = magnitude of vector length dL

= Unit vector in the direction from differential current element to point P

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=

A/m

=

A/m

6. State Biot-Savart law for distributed sources

A/m K Surface current density, dS differential surface

A/m J Volumecurrent density, differential volume

7. State Amperes circuital law8. Write point form and integral form of Amperes circuital law9. What is law of conservation of magnetic flux?10.Differentiate Magnetic scalar potential and Magnetic vector potential11.How do you find the vector potentials, knowing current distribution?12.Write Laplace equation and Poissons equation in magnetic field13.Write down Lorentz force equation and its application14.Define torque in static magnetic field15.Define magnetic dipole moment16.Relate torque and magnetic dipole moment

1. Explain Biot-savart law in vector form and also for distributed sources2. Derive the magnetic field intensity (H) due to infinitely long straight conductor3. Derive the magnetic field intensity (H) due to straight conductor of finite length4. Derive the magnetic field intensity (H) on the axis of the circular loop5. State and prove that Amperes circuital law6. Derive the magnetic field intensity (H) due to infinitely long straight conductor using

Amperes circuital law

7. Derive the magnetic field intensity (H) due to infinite sheet of current using Amperescircuital law

8. Derive the magnetic field intensity (H) due to Co-axial cable using Amperes circuitallaw

9. State and explain Gauss law for magnetic field10.Explain Magnetic scalar potential and Magnetic vector potential

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11.Explain Lorentz force equation on a moving point charge and differential current element12.Derive the force on a wire carrying current I in magnetic field13.Derive the torque and magnetic moment on a loop carrying current I in magnetic field