MCQOPTIONS
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MCQOPTIONS
This section includes 36 Mcqs, each offering curated multiple-choice questions to sharpen your Electromagnetic Theory knowledge and support exam preparation. Choose a topic below to get started.
| 1. |
A plane wave propagating in the dielectric medium has an electric field given as Ex = E0 cos (3 × 1010 t - 100 z). The dielectric constant of the medium is: |
| A. | 1.33 |
| B. | 1 |
| C. | 1.01 |
| D. | 2.15 |
| Answer» C. 1.01 | |
| 2. |
A plane wave propagating in the dielectric medium has an electric field given as Ex = E0 cos (2.6 × 1010 t - 100 z). The phase velocity of plane wave is: |
| A. | 106 m / sec |
| B. | 2.6 × 108 m / sec |
| C. | 3.0 × 108 m / sec |
| D. | 4.0 × 108 m / sec |
| Answer» C. 3.0 × 108 m / sec | |
| 3. |
A lossless transmission line has the distributed circuit parameters of inductance and capacitance per meter as 625 nH/m and 64 pF/m respectively, the phase constant of the line at 100 MHz is: |
| A. | 3.97 rad/m |
| B. | 18.42 rad/m |
| C. | 1.56 rad/m |
| D. | 9.21 rad/m |
| Answer» B. 18.42 rad/m | |
| 4. |
A plane wave is characterized by:\(\bar E = (0.5 \hat x + \hat y e^{j\pi / 2}) e^{jwt - jkz}\)The wave is |
| A. | Linearly Polarized |
| B. | Circularly polarized |
| C. | Unpolarized |
| D. | Elliptically Polarized |
| Answer» E. | |
| 5. |
A plane wave with a frequency of 3 GHz is propagating in an unbounded medium with relative permittivity εr = 6 and permeability μr = 1.5, the phase velocity for this wave in this medium is |
| A. | 1 × 108 m/s |
| B. | 2 × 108 m/s |
| C. | 3 × 108 m/s |
| D. | 1.5 × 108 m/s |
| Answer» B. 2 × 108 m/s | |
| 6. |
An elliptically (arbitrarily) polarized wave can be broken up into |
| A. | Two circularly polarized components rotating in same direction |
| B. | two circularly polarized components rotating in opposite directions |
| C. | Two stationary circularly polarized components |
| D. | None of these |
| Answer» C. Two stationary circularly polarized components | |
| 7. |
If a sky wave with a frequency of 50 MHz is incident on the D-region at an angle of 30°, then the angle of refraction is: |
| A. | 50° |
| B. | 60° |
| C. | 30° |
| D. | 5.5° |
| Answer» D. 5.5° | |
| 8. |
If a right hand circularly polarized wave is incident on a perfect conductor. The reflected wave is: |
| A. | Right circularly polarised wave |
| B. | Left circularly polarised wave |
| C. | Linear polarised wave |
| D. | None of above |
| Answer» C. Linear polarised wave | |
| 9. |
If maximum and minimum voltages on a transmission line are 4 V and 2 V respectively, VSWR is |
| A. | 0.5 |
| B. | 2 |
| C. | 1 |
| D. | 8 |
| Answer» C. 1 | |
| 10. |
Consider the following statements regarding the depth of penetration or skin depth in a conductor1. It increases as frequency increases.2. It is inversely proportional to the square root of μ and σ.3. It is inversely proportional to the square root of f.4. It is directly proportional to the square root of μ and σ.Which of the above statements are correct? |
| A. | 1 and 2 only |
| B. | 3 and 4 only |
| C. | 2 and 3 only |
| D. | 1, 2, 3 and 4 |
| Answer» D. 1, 2, 3 and 4 | |
| 11. |
If reflection coefficient is 1/5 then corresponding VSWR is given by ______ |
| A. | 1 |
| B. | 2 |
| C. | 3 |
| D. | 3/2 |
| Answer» E. | |
| 12. |
Consider the following statements:1. (Electric or magnetic) field must have two orthogonal linear components.2. The two components must have the same magnitude.3. The two components must have a time-phase difference of odd multiples of 90°Which of these are the necessary and sufficient conditions for a time-harmonic wave to be circularly polarized at a given point in space ? |
| A. | 1 and 2 only |
| B. | 2 and 3 only |
| C. | 1, 2 and 3 |
| D. | 1 and 3 only |
| Answer» D. 1 and 3 only | |
| 13. |
A plane wave of frequency 2 GHz travelling in air parallel to a flat ground plane with H parallel to the ground plane losses 3 μW / m2 into the ground plane having conductivity σ = 107 Ʊ / m, μr = ϵr = 1. The following data is given:A) E = 4.106 × 10-4 V/m B) E = 8.98 V / mC) H = 1.089 × 10-6 A/m D) H = 3.97 mA / mChoose the most appropriate answer from the options given below: |
| A. | (A) and (C) only |
| B. | (A) and (D) only |
| C. | (B) and (C) only |
| D. | (B) and (D) only |
| Answer» B. (A) and (D) only | |
| 14. |
A transmission line whose characteristic impedance is 100 Ω has 300 Ω terminating load. What is the percentage of reflected voltage? |
| A. | 33.3% |
| B. | 50% |
| C. | 66.6% |
| D. | 55% |
| Answer» C. 66.6% | |
| 15. |
If a right-handed circularly polarized wave is incident normally on a plane perfect conductor, then the reflected wave will be |
| A. | right-handed circularly polarized |
| B. | left-handed circularly polarized |
| C. | elliptically polarized with a tilt angle of 45° |
| D. | horizontally polarized |
| Answer» C. elliptically polarized with a tilt angle of 45° | |
| 16. |
A uniform plane wave at the boundary of an overhead transmission line and underground cable has reflection coefficient: γ. The standing wave ratio is |
| A. | \(\frac{{\left( {1 - \gamma } \right)}}{{\left( {1 + \gamma } \right)}}\) |
| B. | \(\frac{{\left( {1 - \left| \gamma \right|} \right)}}{{\left( {1 + \left| \gamma \right|} \right)}}\) |
| C. | \(\frac{{\left( {1 + \left| \gamma \right|} \right)}}{{\left( {1 - \left| \gamma \right|} \right)}}\) |
| D. | \(\frac{{\left( {1 + {\gamma ^2}} \right)}}{{\left( {1 - \gamma } \right)}}\) |
| Answer» D. \(\frac{{\left( {1 + {\gamma ^2}} \right)}}{{\left( {1 - \gamma } \right)}}\) | |
| 17. |
Ideal value of VSWR is |
| A. | 0 |
| B. | 1 |
| C. | Infinity |
| D. | 10 |
| Answer» C. Infinity | |
| 18. |
For a plane wave propagating in an unbounded medium (say, free space), the minimum angle between electric field and magnetic field vectors is |
| A. | 0° |
| B. | 60° |
| C. | 90° |
| D. | 180° |
| Answer» D. 180° | |
| 19. |
Determine polarization loss factor for a circularly polarized signal upon reception by linearly polarized antenna |
| A. | \(\frac{1}{{\sqrt 2 }}\) |
| B. | \(\frac{1}{2}\) |
| C. | 1 |
| D. | 0 |
| Answer» C. 1 | |
| 20. |
For an EM wave ray traversing from air, medium 1 to a conducting Medium 2.Following statements are given:(A) \(E_t ≃ \frac{2Z_c}{Z_0}E_i\)(B) \(E_r= \frac{Z_c-Z_0}{Z_c+Z_0}E_i\)(C) \(E_r= \frac{Z_c}{Z_c+Z_0}E_i\)(D) Ht ≃ 2Hi(E) Ht ≃ HiChoose the most appropriate answer from the options given below: |
| A. | (A), (B), (D) only |
| B. | (A), (C), (E) only |
| C. | (A), (B), (E) only |
| D. | (B), (C), (D) only |
| Answer» B. (A), (C), (E) only | |
| 21. |
In a fiber-optic cable, which phenomenon occurs for signal to propagate along the inner core: |
| A. | Modulation |
| B. | Reflection |
| C. | Refraction |
| D. | All of the above |
| Answer» C. Refraction | |
| 22. |
For no reflection condition, a vertically polarized wave should be incident at the interface between two dielectrics having ϵ1 = 4 and ϵ2 = 9, with an incident angle of |
| A. | \(tan^{-1}(\frac{9}{4})\) |
| B. | \(tan^{-1}(\frac{3}{2})\) |
| C. | \(tan^{-1}(\frac{2}{3})\) |
| D. | \(tan^{-1}(\frac{4}{9})\) |
| Answer» C. \(tan^{-1}(\frac{2}{3})\) | |
| 23. |
An ideally matched load is one in which |
| A. | reflection is zero |
| B. | reflection is unity |
| C. | partial reflection and partial transmission |
| D. | none of these |
| Answer» B. reflection is unity | |
| 24. |
plane wave is generated under water (ϵ = 81 ϵ0 and μ = μ0) The wave is parallel polarized. At the interface between water and air, the angle a for which there is no reflection is |
| A. | 83.88° |
| B. | 83.66° |
| C. | 84.86° |
| D. | 84.08° |
| Answer» C. 84.86° | |
| 25. |
A uniform plane wave in air impinge at 45° angle on a lossless dielectric material with dielectric constant εr. The transmitted wave propagates at a 30° direction with respect to the normal. The value of ϵr is: |
| A. | 1.5 |
| B. | \(\sqrt {1.5} \) |
| C. | 2 |
| D. | √2 |
| Answer» D. √2 | |
| 26. |
A person is six fet tall. The minimum height of a vertical mirror for viewing his entire length in the mirror is - |
| A. | 6 ft |
| B. | 4.5 ft |
| C. | 7.5 ft |
| D. | 3 ft |
| Answer» E. | |
| 27. |
A wave is incident from free-space onto a dielectric region of dielectric constant εr = 4, The wave impedance in the dielectric is: |
| A. | 55.5 Ω |
| B. | 100.5 Ω |
| C. | 108.6 Ω |
| D. | 188.5 Ω |
| Answer» E. | |
| 28. |
Phase velocity vp, and group velocity vg in a waveguide are related to the velocity of light c as: |
| A. | vp vg = c2 |
| B. | vp + vg = c |
| C. | \(\frac{{{v_p}}}{{{v_g}}} =\) Constant |
| D. | vp+ vg = Constant |
| Answer» B. vp + vg = c | |
| 29. |
In Free space, H = 0.1 cos (ωt – βx) az A/m (ax, ay, az are unit vectors along x, y, and z-axis respectively)The Total power passing through a square plate of side 10 cm on plane x + 2y = 1.0 is, approximately: |
| A. | 42.12 mW |
| B. | 16.85 mW |
| C. | 18.84 mW |
| D. | 8.425 mW |
| Answer» E. | |
| 30. |
For an elliptically polarized wave incident on the interface of a dielectric at the Brewster angle, the reflected wave will be |
| A. | elliptically polarized |
| B. | linearly polarized |
| C. | right circularly polarized |
| D. | left circularly polarized |
| Answer» B. linearly polarized | |
| 31. |
A plane wave E = 100 sin (ωt – 10x) V/m in a loss less medium with μ = 4 μ0, ε = ε0 strikes another medium with 90 degree angle of incidence having μ = 9 μ0, ε = ε0, the reflection co-efficient is: |
| A. | 0.5 |
| B. | 0.25 |
| C. | 0.1 |
| D. | 0.2 |
| Answer» E. | |
| 32. |
A steel pipe is constructed of a material for which μr = 200 and σ = 5 × 106 mho/m. The outer and inner radii are 8 and 6 mm respectively and the length is 80 m. If the total current carried by the pipe is 2cos104 πt A, Then the skin depth will be |
| A. | 0.225 × 10-3 m |
| B. | 0.300 × 10-3 m |
| C. | 0.352 × 10-3 m |
| D. | 0.125 × 10-3 m |
| Answer» B. 0.300 × 10-3 m | |
| 33. |
A ray of light incident on a glass slab ( of refractive index 1.5 ) with an angle of incidence \(\frac{\pi}{4}\) then the value of sine of angle of refraction is : |
| A. | \(\frac{1}{\sqrt2}\) |
| B. | \(\frac{3}{\sqrt2}\) |
| C. | \(\frac{\sqrt2}{3}\) |
| D. | \(\sqrt2\) |
| Answer» D. \(\sqrt2\) | |
| 34. |
If the electric field of a plane wave is\(\vec E\left( {z,\;t} \right) = \hat x\;3\cos \left( {\omega t - kz + 30^\circ } \right) - \hat y4\sin \left( {\omega t - kz + 45^\circ } \right)\left( {mV/m} \right)\)The polarization state of the plane wave is |
| A. | left elliptical |
| B. | left circular |
| C. | right elliptical |
| D. | right circular |
| Answer» B. left circular | |
| 35. |
Consider a transmission line of characteristic impedance 50 ohm. Let it be terminated at one end by j 50 ohm. The VSWR produced by it in the transmission line will be |
| A. | +1 |
| B. | 0 |
| C. | ∞ |
| D. | +j |
| Answer» D. +j | |
| 36. |
A solid conductor with relative permeability μr = 200, conductivity σ = 5 × 106 mho/m having outer diameter 8 mm and length 2 mm. If the total current carried by the conductor is i(t) = 2 cos (π 104 t) A. Find the skin depth. |
| A. | 2.25 mm |
| B. | 0.225 mm |
| C. | 0.16 mm |
| D. | 1.60 mm |
| Answer» C. 0.16 mm | |