Electromagnetics Objectives 02

21 . The magnitude of the intrinsic impedance of a good conducting medium is given by√ꙍμꝊ.

22 . Which of the following represents the continuity equations for discrete components?∇. J= 0.

23 . Which of the following equation represents the relation between the magnetizing volume current density Jm and the magnetization polarization M?Jm= ∇x M
Question 24 to 25 refer to data given below:

24 . It is given that for rural ground er=14 at low frequency and = 10-2. At which frequency the behavior of rural ground will be like a conductor 1 kHz.

25 . At which frequency it behaves like a dielectric? 30 MHz.

26 . The characteristics impedance of the free space is taken as 377 ohms.

27 . The vector product of electric intensities E and magnetic field intensity H at any point is a measure of the rate of energy flow per unit area at that point. The above statement is known asPoynting theorem.

28 . The Poynting vector P measures the rate of flow of energy.

29 . The ratio of the velocity of a wave in free-space to that in the conducting medium is knowns as refractive index .

30. Which of the following is not Maxwell’s equation?∇ . E = -B.

31 . Which of the following is not Maxwell’s equation?E=εD.

32 . Poynting vector signifies power density vector producing electro-magnetic field.

33 . Poynting vector has the units of watts/metre2.

34 . Poynting vector gives the rate of energy flow.

35. Maxwell’s equation in free space is ∇ .B = 0.

36 . ∇2 . H= μ0 ε0∂2H∂𝑡2 is a wave equation.

37 . Poynting theorem relating the electric intensity E, magnetic intensity H and the rate of energy flow per unit area at a point gives pointing vector P as equal to E x H.

38 . Which of the following represents the Maxwell’s continuity equation for time varying electromagnetic fields, Δ.J +𝛛𝒑𝛛𝒕 = 0.

39 . Velocity of plane electromagnetic waves in vacuum equals√μ0 ε0 .

40 . Where two sinusoidally time varying vectors having different amplitudes and phases are added up, the resulting vector is elliptically polarized.