Test: Lossy And Lossless Dielectrics


12 Questions MCQ Test Electromagnetic Theory | Test: Lossy And Lossless Dielectrics


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This mock test of Test: Lossy And Lossless Dielectrics for Electrical Engineering (EE) helps you for every Electrical Engineering (EE) entrance exam. This contains 12 Multiple Choice Questions for Electrical Engineering (EE) Test: Lossy And Lossless Dielectrics (mcq) to study with solutions a complete question bank. The solved questions answers in this Test: Lossy And Lossless Dielectrics quiz give you a good mix of easy questions and tough questions. Electrical Engineering (EE) students definitely take this Test: Lossy And Lossless Dielectrics exercise for a better result in the exam. You can find other Test: Lossy And Lossless Dielectrics extra questions, long questions & short questions for Electrical Engineering (EE) on EduRev as well by searching above.
QUESTION: 1

For a dielectric, the condition to be satisfied is

Solution:

Answer: b
Explanation: In a dielectric, the conductivity will be very less. Thus the loss tangent will be less than unity. This implies σ/ωε < 1 is true.

QUESTION: 2

For a perfect dielectric, which parameter will be zero?

Solution:

Answer: a
Explanation: The conductivity will be minimum for a dielectric. For a perfect dielectric, the conductivity will be zero.

QUESTION: 3

Calculate the phase constant of a wave with frequency 12 rad/s and velocity 3×108 m/s(in 10-8 order)

Solution:

Answer: c
Explanation: The phase constant is given by β = ω√(με), where ω is the frequency in rad/s and 1/√(με) is the velocity of wave. On substituting √(με) = 3×108 and ω = 12, we get β = 12/(3×108) = 4 x 10-8m/s.

QUESTION: 4

For a lossless dielectric, the attenuation will be

Solution:

Answer: b
Explanation: The attenuation is the loss of power of the wave during its propagation. In a lossless dielectric, the loss of power will not occur. Thus the attenuation will be zero.

QUESTION: 5

Calculate the velocity of a wave with frequency 2 x109 rad/s and phase constant of 4 x 108units.

Solution:

Answer: b
Explanation: The velocity of a wave is the ratio of the frequency to the phase constant. Thus V = ω/β. On substituting the given values, we get V = 2 x109/ 4 x 108 = 5 units.

QUESTION: 6

Which of the following is the correct relation between wavelength and the phase constant of a wave?

Solution:

Answer: a
Explanation: The phase constant is the ratio of 2π to the wavelength λ. Thus β = 2π/λ is the correct relation

QUESTION: 7

In lossy dielectric, the phase difference between the electric field E and the magnetic field H is

Solution:

Answer: d
Explanation: In a lossy dielectric, the E and H component will be in phase. This implies that the phase difference between E and H will be 0.

QUESTION: 8

The intrinsic impedance is the ratio of square root of

Solution:

Answer: b
Explanation: The intrinsic impedance is the impedance of a particular material. It is the ratio of square root of the permeability to permittivity. For air, the intrinsic impedance is 377 ohm or 120π.

QUESTION: 9

Calculate the skin depth of a material with attenuation constant of 2 units.

Solution:

Answer: c
Explanation: The skin depth of a material is the reciprocal of the attenuation constant. Thus δ = 1/α. On substituting for α = 2, we get δ = ½ = 0.5 units.

QUESTION: 10

Calculate the phase constant of a wave with skin depth of 2.5 units.

Solution:

Answer: d
Explanation: The skin depth is the reciprocal of the phase constant and the attenuation constant too. Thus δ = 1/β. On substituting for δ = 2.5, we get β = 1/δ = 1/2.5 = 2/5 units.

QUESTION: 11

An example for lossless propagation is

Solution:

Answer: d
Explanation: There are many techniques employed to achieve zero attenuation or maximum propagation. But it is not achievable practically. Thus lossless propagation is not possible practically

QUESTION: 12

Skin depth phenomenon is found in which materials?

Solution:

Answer: c
Explanation: Skin depth is found in pure conductors. It the property of the conductor to allow a small amount of electromagnetic energy into its skin, but not completely. This is the reason why EM waves cannot travel inside a good conductor.

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