JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD B.Tech II ELECTROMAGNETIC FIELDS Previous Question Paper (November/December - 2018 - R13)

What is Gauss’s law?

Define potential gradient.

Define capacitance.

What are the dielectric boundary conditions?

What are static magnetic fields?

Define: i) Magnetic flux and ii) Magnetic flux density.

Write two limitations of scalar magnetic potential.

What is magnetic dipole?

What is dynamically induced e.m.f?

Write the equation for displacement current Density.

State and explain coulomb’s law in electro statics.

The non uniform field

Three infinite sheets of charge are located in free space as follows: 3 nC/m² at z = -4, 6 nC/m² at z = 1, and -8 nC/m² at z = 4. Find E at: i) P_A(2,5,-5) ii) P_B(4,2,-3) iii) P_C(-1,-0.5,2) iv) P_D(-2,4,5).

What is electric field intensity? Explain the concept of electric field and write down expression for the electric field due to point charge.

A copper conductor has a diameter of 1.2 cm and it is 1200 m long. Assume that it carries a total current of 50A: i) Find the total resistance of the conductor ii) What current density exists in it?

Derive the ohm’s law in point form.

Determine the capacitance of a capacitor consisting of two parallel metal plates 30 cm × 30 cm surface area, separated by 5mm in air. What is the total energy stored by the capacitor, if the capacitor is charged to a potential difference of 500V? What is energy density?

Define and explain the conduction and Convection current densities.

Derive the expression for magnetic field intensity at the center of a circular wire.

A long solenoid has a radius of 3 mm and a length of 2 cm. If the number of turns per unit length is 400 and the current is 10 A, calculate the magnetic flux density at: i) the Centre and ii) the ends of solenoid.

Find the expression for the magnetic flux density, B at a distance h above the centre of a square loop of wire b meters of each side. The loop carries current of one amperes.

State and explain amperes circuital law and derive the same in point and differential form.

State and explain Lorentz’s force equation.

Derive the expression for energy stored in a magnetic field.

Evaluate the inductance of a solenoid of 2800 turns wound uniformly over a length 0.6 m on a cylindrical paper tube 4 cm in diameter. The medium is air.

Derive an expression for torque developed on a current loop placed in a magnetic field.

A square coil rotates at a constant speed of 500rpm about axis perpendicular to a stationary uniform field of magnetic induction 0.75 Tesla. The coil has mean dimensions of 15 cm × 15 cm and is wound with 100 Turns. Determine dynamically induced emf in the coil when the plane of the coil is: i) in the same plane as the field ii) At right angles to the field iii) inclined 60 degrees to the field.

Find the conduction and displacement current densities in a material having conductivity of 10^-3 s/m and ε_r = 2.5, if the electric field in material is

State and explain Faradays laws of electromagnetic induction.

Derive the Maxwell’s equations in point and integral form for time varying fields.