### 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 as**Poynting theorem.**

**28 . ** The Poynting vector P measure**s 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.**