- A solid sphere made of insulating material has a radius R and has a total charge Q distributed uniformly in its volume. What is the magnitude of electric field intensity, E, at a distance r (o<r<R) inside the sphere?
Let we assume a Gaussian surface inside the sphere (x < R) From Gauss’s law

ψ = Q_{enclosed}

Again Q_{enclosed}= surface integral of (D.ds)

- A plane wave in a homogeneous medium has E = 50 sin(10
^{8}t + 2z) u_{y}V/m. What is the direction of wave propagation?A wave E = 50 sin(10^{8}t – 2z) u_{y}has component of a E in y direction and it travel in z direction. The given wave with +2z shall move in the negative z direction. - If
**n**is the polarization vector and**k**is the direction of propagation plane electromagnetic wave, themThe polarization vector and direction of travel are perpendicular to each other. So, Dot production of two vector is zero. - Which statement is not correct for the transmission line parameter R, L, G and C?
G is not equal to I/R, where G is conductance per unit length of the conductor and is due to the dielectric medium separating the conductor.
- Skin depth is proportional to
Skin depth is given as

. - The frequency of the power wave associated with an electromagnetic wave having field as E = e
^{-z/δ cos(ω - zδ) }is given byHere E = e^{ - zδ cos(ω t – z/δ) }

Where, ω is the radian frequency of E. It is same the radium frequency of the associated H wave. The frequency of power wave is double the corresponding frequency of E or H wave. Thus the radian frequency of 2ω and cyclic frequency = 2ω/2π = ω / π. - An ac voltage source v = v
_{o}sinω+ is connected across a parallel plate capacitor C. If conductor current & i_{d}respectively then which is true among following relation?The conduction current in the connecting wire

For Parallel plate capacitor of area A and plate thickness d,

C = ε A/d

Electric field E in the dielectric is E = v/d.

So, D = ε E = ε (V_{o}/d) sin ωt

Displacement current i_{d}

Therefore, i_{c}= i_{d}. - What is the value of skin depth as 100 Hz in a material having μ
_{r}= 1.0 and &sigma = 3.60 × 10^{7}s/m?Skin depth of a material is given as,

. - A plane wave magnetic field is represented by B
_{x}= cos(y – ct). The electric and magnetic fields will be zero in the directionWave propagating in (+ y) direction.**H**in (+ x) direction Then**E**will be in (+ z) direction.

So, E_{x}= E_{y}= 0 and B_{y}= B_{z}= 0. - Which following statement are not true for line parameters R, L, G and C of transmission line?
For each line LC = μ ε G/c = σ/ε.
- In a lossless medium the intrinsic impedance η 60π and μ
_{r}= 1. The relative dielectric constant ε_{r}shall beFor free space η_{o}= & radiac; (μ/ε = 12 π for any lossless medium with μ_{r}= 1

So ε_{r}= 4. - When a lossy capacitor with a dielectric of permittivity ε and conductivity σ operates at a frequency ω the loss tangent for the capacitor is given by
As C = Aε/d

R = d/(σ A)

CR = A ε/d

d/(&sigma A) = ε/σ

tan δ = I_{R}/I_{c}= V/(R.V&omega c) = I/(ω CR)

So, tan δ = I(ω ε/σ) = σ/(ω ε). - The characteristic impedance of a transmission on line is
Characteristic impedance of transmission line is given as,

So it is independent of length. - For a lossy transmission line, the characteristic impedance does not depend on
A transmission line is said to be lossless if both its conductor and dielectric are lossless or R = O and G = O

So characteristic impedance be,

Inductance and capacitance are not depends the load terminating the line. - For distortion less line which of following relation are true?
A distortionless line is one in which the attention constant α is frequency independent while the phase constant is linearly dependent on frequency. For this line, the condition applicable is R/L = G/C.
- If R = 84 ohm/Km, G = 10
^{-6}mho/Km, H = 0.01 H/Km, C = 0.061 μ F/Km and frequency = 1000 Hz, then what is the value of propagation constant of the transmission line?Z = R + jω L = 84 + j2π 100 × 0.01 = 84 + j 62.83 = 104.9 ∠ 36.8° ohm/Km.

Y = G + jω C = 383.27 × 10^{-6}∠ 89.85° mho/Km.

So propagation constant by γ = &radiac; (yz). - In frec space
**E**(z,t) = 10^{3}sin(ωt - βz) u_{y}v/m. What is the value of**H**(z,t)?Direction of wave propagation (+z). So**E**×**H**must be (+z) direction.

Therefore**E**×**H**must be – u_{x}

Now E_{y}/H_{x}= η_{o}= 377 (As free space)

H_{x}= 10^{3}/377 (A/m). - For a line characteristic impedance z
_{o}terminated is load z_{o}/3, the reflection coefficient is. - The SWR on a lossless transmission line of the characteristic impedance 100 ohm is 3. The line is the terminated by
For a transmission line, reflection co-efficient,

Here Z_{L}= 3 00 Γ_{L}= 200/400 = ½ and SWR = 3. - The VSWR of transmission line is
.

Design with by SARU TECH