QUESTION 1 Assume that sea water has = , = the frequency at which the conduction current density is 10 times the displacement current density in magnitude. (4) QUESTION 2 A conductor with cross-sectional area of 10 cm carries a conduction current 9 0.2 sin sin 10't mA. Given that 0 = 81 0 = 20 S/m, determine 2.510 S/m and = r magnitude of the displacement current density. (5) QUESTION 3 Check whether the following fields are genuine EM fields, i.e., they satisfy Maxwell's equations. Assume that the fields exist in charge-free regions. (2) B ^ (1) A = 40 sin sin (wt + 10x) z = 6, calculate the 10 P (2) cos(wt - 20p) ^ (2) QUESTION 3 Check whether the following fields are genuine EM fields, i.e., they satisfy Maxwell's equations. Assume that the fields exist in charge-free regions. (1) A (2) B = = A 40 sin sin (wt + 10x) z 10 P cos(wt (3) C = (3pcotop + = QUESTION 5 In a nonmagnetic medium, (2) A 20p) coso P QUESTION 4 Show that in a source-free region U = 0, P V (2) (8) (2) 0), Maxwell's equations can be reduced to two. Identify the two all-embracing equations. sinwt (3) (10't - 8x) y + 40 sin cos cos E = 50 cos cos Find the dielectric constant & and the r corresponding H. QUESTION 6 A car is travelling at 120 km/h. If the Earth's -5 2 magnetic field is 4. 310 Wb/m", find the induced voltage in the car bumper of length 1.6 m. Assume that the angle between the earth magnetic field and the normal to the car is 65. (4) QUESTION 7 An EM wave propagating in a certain medium is described by E = 25 sin sin (2x10t - 6x) z V/m 1. Determine the direction of propagation of the wave. (1) 2. Compute the period T, the wavelength A and the velocity v. (3) TTT 3. Sketch the wave at t = 0, 8' 4' 2 (4) QUESTION 8 Show that in a linear homogeneous, isotropic source-free region, both E and H_must S S satisfy the wave equation 2 VA + YA S S A = 0 2 2 where y = w u - jwo and A = E or H jouo S S S (12) TOTAL: 50