### 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 by**tan 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**