Electromagnetics Objectives 03
41 . For an EM wave transmitted in a good dielectric having Ꝋ/(ꙍε) >> 1, the attenuation constant α and phase shift factor β are given byα = Ꝋ𝟐√μ𝛆 ; β = ꙍ √μ 𝛆
42 . A time varying magnetic field produces both magnetic and electric fields.
43 . The following waves don’t exist in waveguides: TEM waves.
44 . For normal incidence, the angle of incidence is 00.
45 . The angle for which there is no reflection and the incident wave is vertically polarized, is known as Brewster angle.
46 . A circularly polarized wave incident at the Brewster angle on reflection becomes linearly polarized.
47 . In a perfect dielectric, wave propagation occurs; with zero attenuation.
. 48. The Brewster angle is given bytan θ= √𝛆𝟐𝛆𝟏 .
49 . A parallel polarized wave is incident from air to paraffin. If εr for paraffin is 2, the Brewster angle will be nearly 550.
50 . Poynting vector has the dimensions Watts/metre2.
51 . Poynting vector is a measure of the rate of energy flow per unit area and is given by P = E x H.
52 . The Poynting vector is associated with power flow in electrostatic field.
53 . The polarization of dielectric materials results in creation of electric dipoles.
54 . According to Snell’s law, for electromagnetic waves
𝐜𝐨𝐬𝛉𝐢𝐜𝐨𝐬𝛉𝐫 = 𝐧𝟏𝐧𝟐
55 . Δ2 v = – pε is known as Poisson’s equation.
56 . The direction of which of the following vector gives the direction of propagation of electromagnetic waves? Vector (E x H).
57 . When n1 and n2 are the refractive indices of two mediums, then according to Snell’s law 𝐬𝐢𝐧𝛉𝐫𝐬𝐢𝐧𝛉𝐢 = 𝐧𝟏𝐧𝟐
58 . The current density J is related with current as J= 𝐈𝐀 .
59 . The energy stored in a magnetic field is given by W= μ 𝐇𝟐𝟐 .
60 . Characteristic equation of plane wave in E, independent of two dimensions y and z, is𝛛𝐄𝛛𝐭=𝟎