### Electromagnetics Objectives Part 01

**01 . ** Mark the correct relation **= j.j = k. k = 1**

* 02 .* Which of the following relation is valid?

**i x j = k**

**03 .** Which of the following relation is valid?**A x (B x C) = (A.C) B – (A.B) C 4. Which of the following **relation is valid?** ∇ x ∇ x A = ∇ (∇. A)- ∇2 A**

**04 .** The magnitude of the vector 3ax+4ay-5az is **7.07.**

**05 .** Which of the following represents the Maxwell’s divergence equation for static electric field? **∇ . B = 0**

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**06 .** Which of the following represents the Maxwell’s curl equation for static magnetic field? **∇x B= μ0 J.**

**07 . ** Which of the following represents the Maxwell’s curl equation for static magnetic field? **∇x B= μ0 J.**

**08 .** Conductivity is measured in terms of **mhos/metre. **

**09.** The magnitude of the vector cosαax +** 2 sinα ay = 7 azwill be 7.21.**

**10 . ** Which of the following relation is valid? **D=εE.**

**11 . ** The component form of the unit vector which is directed along a line from the origin to (**-2,1,2).− 𝟐𝟑𝒂𝒙 + 𝟐𝟑 𝒂𝒚+ 𝟐𝟑 𝒂𝒛.**

**12 . ** The do product of the vectors A and B when A= 3ay -2ax and B= 2 A will be0.

**13 .** A medium behaves like dielectric when** the displacement current is much greater than the conduction current.**

**14 . ** If the magnetic field vector H has only Z component given by H= 3x cosβ + 6y sinγ and if the field is invariant with time, the expression for current density J will be **J=-6 k sin γ.**

**15 .** Which of the following field satisfies Maxwell’s equation?

B=8X104 Y2 + 4 X 109t2

E= 9x1010yt ax

**16 . ** The relative dielectric constant of a non-magnetic material through which a uniform plane wave is propagating and intrinsic impedance is 180 Ω will be **2.25.**

**17 . ** What is the relative dielectric constant of a non-magnetic material through which a uniform plane wave is propagating if the wave-length at 10Hz is 2 cm? **3.65.**

**18 .** The wavelength in a material for which εR = 4, μR=1, f=3×108 Hz and the loss tangent is 0.01, will be** 3.455m.**

**19 .** The percentage of the incident power that is reflected when uniform plane wave travelling in region 1 normally incident on region 2 if region 1 and 2 are respectively**polysterene and air.**

**20 .** In case of semi-conductors the ratio of conduction current to displacement current is** less than 100 but greater than 𝟏𝟏𝟎𝟎.**