SECTION B: ELECTROMAGNETIC FIELD THEORY. Answer any TWO questions from this section. (a) Describe electromagnetic shielding. (b) A uniform wave propagating in free space strikes a lossy medium with a dielectric constant of 20 and conductivity of 0.8 mS/m. The frequency of the wave polarised in the X-direction is 200 kHz. Determine the: (i) angular frequency, ω; (ii) propagation constant, Y; (iii) intrinsic impedance η; (iv) phase velocity, μρ. (c) (i) Outline three sources of electromagnetic radiations; (ii) A conductor of length 10 cm carries a current of 2A in a vertical direction. A point P is placed 1 m away from the conductor in the X-direction. (I) stretch the arrangement; (II) determine the angle between vertical axis and point P; (III) determine magnetic field at point P using Biot-Savart law.

a) Electromagnetic shielding is the process of reducing the electromagnetic field in a space by blocking the field with barriers made of conductive or magnetic materials. It is used to protect electronic devices from external electromagnetic interference or to prevent electromagnetic radiation from escaping a specific area. b) Given: Dielectric constant, _r = 20 Conductivity, = 0.8 \, mS/m = 0.8 × 10^-3 \, S/m Frequency, f = 200 \, kHz = 200 × 10^3 \, Hz Permittivity of free space, $_0 = 8.85