JNTU B.Tech II ELECTROMAGNETIC THEORY AND TRANSMISSION LINES Previous Question Paper (April - 2018 - R15)

Define relaxation time.

For the given vector A = (x+y) a_x + 3a_y + z² a_z, Determine the unit vector in the direction of –A at the cartesian coordinate point (1,1,1).

State Ampere’s circuit law.

A conductor located at x=0.4m, y=0 and 0 < z < 2m, carries a current of 5A in the a_z direction. Along the length of the conductor vector B =2.5 a_z T. Find the torque about the z-axis.

Write the wave equations in free space.

Find the surface impedance of the conductor at 1 GHz, whose μ_r1 and σ₁ = 50 MΩ/m.

Define phase velocity.

What are the primary and secondary constants of transmission line and also draw the equivalent circuit of two wire transmission line.

One end of a lossless transmission line having the characteristic impedance of 75 ohms and length of 1cm is short circuited. At 3 GHz, what is the input impedance at the other end of the transmission line?

What do you mean by impedance matching and mention various impedance matching techniques.

Derive the expression for energy density in electrostatic fields.

Four charges of 10μC are placed at corners of a square, the coordinates of corners are (1,1,0),(1,-1,0),(-1,1,0),(-1,-1,0). Find the force on a charge of 50μC that is placed at (0,0,2).

Define capacitance and derive the expression for capacitance of spherical capacitor.

Given vectors A = 3a_y + 4a_z and B = 4a_x -10a_y + 5a_z, determine (i) The vector component of A in the direction of B (ii) A unit vector perpendicular to both A and B.

Find H at (-3,4,0) due to current element along x-axis.

Derive an expression for the magnetic field produced by a straight current carrying conductor at a distance x from it.

Given E = 10 sin (ωt - βz) a_y V/m in free space, determine D, B and H.

State and explain Faraday’s law of electromagnetic induction.

Describe the wave propagation in good conducting medium.

Find ratio of E_r/E_i and E_t/E_i at the boundary for the normal incidence. For region 1, ε_r1 = 9, μ_r1 and σ₁ = 0, region 2 is free space. Assume perpendicular polarization.

Explain about elliptical polarization.

A large copper with σ = 5.8 × 10⁷ S/m and ε_r = μ_r = 1 supports a uniform plane wave at 60Hz. Determine the attenuation constant, phase constant and propagation constant.

Describe the low loss characterization of transmission line.

A lossless line has Z₀ = 50Ω and β = 0.2π m^-1 at f = 60 MHz. Find the distributed parameters L and C of the line.

Derive the expression for characteristic impedance in terms of primary constants and angular frequency.

For a transmission line R = 0.1Ω, C = 10pF, L = 0.2μH and G = 0.02. Find the propagation constant and characteristic impedance at 1MHz.

Derive the expressions for reflection coefficient of a transmission line.

Calculate the reflection coefficient and VSWR for 25 Ω line is terminated with: (i) matched load (ii) short circuited load (iii) open circuited load.

Explain about double stub matching technique.

Explain the properties of λ/2, λ/4, λ/8 lines and write their significance.