MCQOPTIONS
Saved Bookmarks
MCQOPTIONS
This section includes 58 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. |
For fiber optical sensors ___________ |
| A. | multimode transmission is used |
| B. | single mode transmission is used |
| C. | both single and multimode transmission is commonly used |
| D. | none of these |
| Answer» C. both single and multimode transmission is commonly used | |
| 2. |
In which of the following, the density of the core remains constant from the center to the edges? |
| A. | Single mode fiber |
| B. | Multimedia step-index fiber |
| C. | Multimode graded index fiber |
| D. | Single mode step index fiber |
| Answer» C. Multimode graded index fiber | |
| 3. |
Out of the following, which light is used for the optical fibre communication? |
| A. | Tube light |
| B. | Laser light |
| C. | Bulb light |
| D. | Sunlight |
| Answer» C. Bulb light | |
| 4. |
For TE10 mode of propagation in a rectangular waveguide filled with air, the broader dimension is 2 cm. The cut-off frequency is |
| A. | 7.5 GHz |
| B. | 7.5 MHz |
| C. | 750 GHz |
| D. | 0.75 GHz |
| Answer» B. 7.5 MHz | |
| 5. |
Match the two lists and choose the correct answer from the code given below:List IList II(a) V-number(i) V2/2(b) Birefringence(ii) x1√(2Δ)(c) No. of modes(iii) (ny – nx)(d) N.A.(iv)\( \frac{{2\pi a}}{{{\lambda_c}}}\times NA\) |
| A. | (a) – (iii), (b) – (iv), (c) – (ii), (d) – (i) |
| B. | (a) – (iv), (b) – (iii), (c) – (i), (d) – (ii) |
| C. | (a) – (i), (b) – (ii), (c) – (iv), (d) – (iii) |
| D. | (a) – (ii), (b) – (i), (c) – (iv), (d) – (iii) |
| Answer» C. (a) – (i), (b) – (ii), (c) – (iv), (d) – (iii) | |
| 6. |
For a 300 m optical fibre cable with BLP of 600 MHz-km, the bandwidth will be |
| A. | 8 GHz |
| B. | 6 GHz |
| C. | 4 GHz |
| D. | 2 GHz |
| Answer» E. | |
| 7. |
For an optical fiber, the following statements are given:(i) Propagation constant is dependent on the wavelength(ii) Propagation constant is independent of the wavelength(iii) \(GVD =- \frac{2\pi c}{\lambda}\beta_2\)(iv) \(GVD =- \frac{2\pi c}{\lambda^2}\beta_2\)Which of the above statements are correct?Choose the correct answer from the code given below: |
| A. | (ii) and (iii) |
| B. | (i) and (iii) |
| C. | (i) and (iv) |
| D. | (ii) and (iv) |
| Answer» D. (ii) and (iv) | |
| 8. |
As the wave frequency approaches to cut-off frequency of wave guide, the correct statement is: |
| A. | The phase velocity of waves tends to zero. |
| B. | The phase velocity of waves tends to velocity of light. |
| C. | The phase velocity of waves tends to infinite. |
| D. | None of these. |
| Answer» D. None of these. | |
| 9. |
Optic fibres are used in: |
| A. | CAT scans |
| B. | X-ray photos |
| C. | Ultrasound scans |
| D. | Endoscopy |
| Answer» E. | |
| 10. |
Indicate which one of the following modes do NOT exist in a rectangular resonant cavity |
| A. | TE110 |
| B. | TE011 |
| C. | TM110 |
| D. | TM111 |
| Answer» B. TE011 | |
| 11. |
Graded index fiber is used to |
| A. | Reduce absorption and resulting power loss |
| B. | Reduce dispersion and thereby increase the data rate |
| C. | Establish secure communication |
| D. | Increase the numerical aperture |
| Answer» C. Establish secure communication | |
| 12. |
Optical fibres are preferred as communication links for Lasers because they: |
| A. | prevent interference by other Lasers |
| B. | ensure that the beam does not spread |
| C. | prevent atmospheric interference |
| D. | ensure amplification of the signal |
| Answer» D. ensure amplification of the signal | |
| 13. |
Consider a rectangular waveguide of internal dimensions 8 cm × 4 cm. assuming an H10 mode of propagation the critical wavelength would be |
| A. | 8 cm |
| B. | 16 cm |
| C. | 4 cm |
| D. | 32 cm |
| Answer» C. 4 cm | |
| 14. |
In a dispersive medium, the group velocity is: |
| A. | less than the phase velocity only |
| B. | equal to the phase velocity only |
| C. | more than the phase velocity, depending on the nature of the dispersive medium |
| D. | more than the phase velocity |
| Answer» B. equal to the phase velocity only | |
| 15. |
Consider an air-filled rectangular waveguide with dimensions a = 2.286 cm and b = 1.016 cm. The increasing order of the cut-off frequencies for different modes is |
| A. | TE01 < TE10 < TE11 < TE20 |
| B. | TE20 < TE11 < TE10 < TE01 |
| C. | TE10 < TE20 < TE01 < TE11 |
| D. | TE10 < TE11 < TE20 < TE01 |
| Answer» D. TE10 < TE11 < TE20 < TE01 | |
| 16. |
In a single-mode optical fiber, the zero-dispersion wavelength refers to the wavelength at which the |
| A. | material dispersion is zero |
| B. | waveguide dispersion is zero |
| C. | sum of material dispersion and wave guide dispersion is zero |
| D. | material dispersion and waveguide dispersion are simultaneously zero |
| Answer» D. material dispersion and waveguide dispersion are simultaneously zero | |
| 17. |
A rectangular waveguide has dimensions of 5.1 cm × 2.4 cm. For the dominant mode TE10 , the cut-off frequency is |
| A. | 2.94 GHz |
| B. | 5.88 GHz |
| C. | 6.25 GHz |
| D. | 68.99 GHz |
| Answer» B. 5.88 GHz | |
| 18. |
In an optical fibre, the pulse dispersion effect is minimized by1. Using a high frequency light source2. Using plastic cladding3. Minimizing the core diameterWhich of the above statements is/are correct? |
| A. | 1 only |
| B. | 2 only |
| C. | 3 only |
| D. | 1, 2 and 3 |
| Answer» D. 1, 2 and 3 | |
| 19. |
For a parallel plate transmission line, let v be the speed of propagation and Z be the characteristic impedance. Neglecting fringe effects, a reduction of spacing between the plates by a factor of two results in |
| A. | halving of v and no change in Z |
| B. | no change in v and halving of Z |
| C. | no change in both v and Z |
| D. | halving of both v and Z |
| Answer» C. no change in both v and Z | |
| 20. |
Direction: Two statements are given. Based on the given information, choose the correct answer.Statement (I): Single-mode step indexed fibers are widely used for wideband communications.Statement (II): With the only path of light along the axis, minimum refraction, and no pulse spreading permits high pulse repetition rates. |
| A. | Both Statement (I) and Statement (II) are individually true and Statement (II) is the correct explanation of Statement (I) |
| B. | Both Statement (I) and Statement (II) are individually true but Statement (II) is NOT the correct explanation of Statement (I) |
| C. | Statement (I) is true but Statement (II) is false |
| D. | Statement (I) is false but Statement (II) is true |
| Answer» B. Both Statement (I) and Statement (II) are individually true but Statement (II) is NOT the correct explanation of Statement (I) | |
| 21. |
Degenerate mode in rectangular waveguides is: |
| A. | TMmn (m = 0, n = 1) |
| B. | TEmn and TMmn (both m ≠ 0) |
| C. | TEmn and TMmn (both m ≠ 0, n ≠ 0) |
| D. | TEmn (m = 1, n = 0) |
| Answer» D. TEmn (m = 1, n = 0) | |
| 22. |
An air filled rectangular waveguide of dimension 7 × 3.5 cm2 operates in the dominant TE10 mode. The value of phase velocity of the wave in the guide at a frequency of 3.5 GHz is given by: |
| A. | 3.78 × 108 m/S |
| B. | 6.78 × 105 m/S |
| C. | 5.78 × 108 m/S |
| D. | 4.78 × 108 m/S |
| Answer» B. 6.78 × 105 m/S | |
| 23. |
For a single mode optical cable with 0.25 dB/km loss, the optical power 100 km from a 0.1 mW source will be _______. |
| A. | -30 dBm |
| B. | -35 dBm |
| C. | -40 dBm |
| D. | -45 dBm |
| Answer» C. -40 dBm | |
| 24. |
For which of the following reasons, losses in optical fibers can be caused?1. Impurities2. Attenuation in glass3. Micro bending4. Stepped index operation |
| A. | 1, 2 and 3 only |
| B. | 1, 3 and 4 only |
| C. | 1, 2 and 4 only |
| D. | 2, 3 and 4 only |
| Answer» B. 1, 3 and 4 only | |
| 25. |
Electromagnetic waves are transverse in nature due to |
| A. | Reflection |
| B. | Diffraction |
| C. | Interference |
| D. | Polarization |
| Answer» E. | |
| 26. |
A rectangular waveguide of internal dimensions (a = 4 cm and b = 3 cm) is to be operated in TE11 mode. The minimum operating frequency is: |
| A. | 6.25 GHz |
| B. | 6.0 GHz |
| C. | 5.0 GHz |
| D. | 3.75 GHz |
| Answer» B. 6.0 GHz | |
| 27. |
Light is confined within the core of an optical fiber due to |
| A. | Refraction |
| B. | Scattering |
| C. | Diffraction |
| D. | Total internal reflection at the core, cladding boundary |
| Answer» E. | |
| 28. |
In the structure of the fiber optic cable, the refractive index of the core is always ______ the refractive index of the cladding. |
| A. | Less than |
| B. | Equal to |
| C. | Greater than |
| D. | None of the above |
| Answer» D. None of the above | |
| 29. |
Consider the rectangle cavity as shown below:If a = c > b, The Dominant mode of resonance corresponding to the above Rectangular cavity is |
| A. | TE011 |
| B. | TE101 |
| C. | TM110 |
| D. | TM011 |
| Answer» C. TM110 | |
| 30. |
Find the maximum possible core diameter which allows single_mode operation at a wavelength of 1.3 μm in a graded-index fiber having a parabolic refractive index profile core with core refractive index at the core axis of 1.5 and relative index difference of 1%. |
| A. | 2.5 μm |
| B. | 3.3 μm |
| C. | 5 μm |
| D. | 6.6 μm |
| Answer» E. | |
| 31. |
_______ is used to describe the light gathering or light collecting ability of an optical fiber |
| A. | Critical angle |
| B. | Cut-off wavelength |
| C. | Numerical Aperture |
| D. | Acceptance angle |
| Answer» D. Acceptance angle | |
| 32. |
In optical communication, the maximum angle in which external light rays may strike the air/glass interface and still propagate down the fiber is called as |
| A. | critical angle |
| B. | numerical aperture |
| C. | angle of refraction |
| D. | acceptance angle |
| Answer» E. | |
| 33. |
Directions: Each of the items consist of two statements, one labeled as the ‘Statement (I)' and the other as ‘Statement (II)’ Examine these two statements carefully and select the answers to these items using the codes given below:Statement (I): In TEmn modes Z component of the magnetic field is non-zero.Statement (II): In TEmn modes Z component of the electric field is non-zero. |
| A. | Both Statement (I) and Statement (II) are individually true and Statement (II) is the correct explanation of Statement (I) |
| B. | Both Statement (I) and Statement (II) are individually true but Statement (II) is not the correct explanation of Statement (I) |
| C. | Statement (I) is true but Statement (II) is false |
| D. | Statement (I) is false but Statement (II) is true |
| Answer» D. Statement (I) is false but Statement (II) is true | |
| 34. |
In case of optical fiber transmission link LED’s and LASER’s are used as ______ |
| A. | Detectors |
| B. | Sources |
| C. | Repeaters |
| D. | Amplifiers |
| Answer» C. Repeaters | |
| 35. |
Light travels along optical fibers by |
| A. | Refraction |
| B. | Reflection |
| C. | Scattering |
| D. | Total internal reflection |
| Answer» E. | |
| 36. |
Fibers having numerical aperture (N.A.) in the region of 0.15 to 0.4. Fibers with higher N.A. values generally exhibit |
| A. | Reduced bandwidth |
| B. | High bandwidth |
| C. | Reduced losses and low bandwidth |
| D. | Greater losses and low bandwidth |
| Answer» D. Greater losses and low bandwidth | |
| 37. |
Polarization mode dispersion (PMD) is mainly observed in: |
| A. | Multiple step-index fiber |
| B. | Single mode fiber |
| C. | Multimode graded-index fiber |
| D. | Plastic fiber |
| Answer» C. Multimode graded-index fiber | |
| 38. |
Optical Time domain Reflectometer is used to measure: |
| A. | Wavelength |
| B. | Dispersion in optical fibre |
| C. | Eye Pattern |
| D. | Loss in optical Communication |
| Answer» E. | |
| 39. |
Fibre is preferred over electrical cabling when _______ bandwidth, _______ distance or _______ to electromagnetic interference is required. |
| A. | low, long, immunity |
| B. | low, short, stability |
| C. | high, long, immunity |
| D. | high, short, stability |
| Answer» D. high, short, stability | |
| 40. |
A non dispersive media has: |
| A. | Group velocity > phase velocity |
| B. | Group velocity < phase velocity |
| C. | Group velocity = phase velocity |
| D. | None of above |
| Answer» D. None of above | |
| 41. |
Optical fibers rely for their operation on the phenomenon of |
| A. | Reflection |
| B. | Refraction |
| C. | Dispersion |
| D. | Total internal reflection |
| Answer» E. | |
| 42. |
Fiber optic of network forms part of which layer is OSI model |
| A. | Physical |
| B. | Network |
| C. | Data link |
| D. | Transport |
| Answer» B. Network | |
| 43. |
In graded index multimode optical fiber, the refractive index of the core is |
| A. | uniform across its radial distance, except for the cladding |
| B. | maximum at the fiber axis and decreases stepwise towards the cladding |
| C. | maximum at the fiber axis and decreases gradually towards the cladding |
| D. | maximum at the fiber axis and increases stepwise towards the cladding |
| Answer» D. maximum at the fiber axis and increases stepwise towards the cladding | |
| 44. |
Consider the following advantages of optical fiber-cables :1. Small diameter2. Immunity to cross talk and electromagnetic interference. 3. Laser and LED modulation methods to lend themselves ideally to digital operation. Which of these advantages are correct? |
| A. | 1 and 2 only |
| B. | 2 and 3 only |
| C. | 3 and 1 only |
| D. | 1, 2 and 3 |
| Answer» E. | |
| 45. |
A micro-strip line consists of a single ground plane and a thin strip conductor on a |
| A. | conducting plane |
| B. | semiconductor slab |
| C. | low-loss dielectric substrate |
| D. | high-loss dielectric substrate |
| Answer» D. high-loss dielectric substrate | |
| 46. |
Main advantage of fiber optic cable over co-axial cable is |
| A. | Easy handling |
| B. | Less weight |
| C. | Easy testing |
| D. | Low loss |
| Answer» E. | |
| 47. |
Due to the phenomenon of refraction of radio: waves in the atmosphere, which of the following effect is observed ? |
| A. | Radio horizon distance is more than the optical horizon distance. |
| B. | Radio horizon distance is less than the optical horizon distance. |
| C. | It all depends upon the weather conditions, Any one of the above choice may be true depending upon . type of weather. |
| D. | Radio horizon and optical horizon are always same because both radio waves and optical waves are electromagnetic in nature, |
| Answer» B. Radio horizon distance is less than the optical horizon distance. | |
| 48. |
For a 3-um-diameter optical fiber with core and cladding indexes of refraction of 1.545 and 1.510, respectively. The cut off wavelength is. |
| A. | 2.3 um |
| B. | 1.29 um |
| C. | 1.5 um |
| D. | 3.24 um |
| Answer» C. 1.5 um | |
| 49. |
In a graded index fiber the reflected light at the core-cladding interface takes a |
| A. | Straight line path |
| B. | Parabolic path |
| C. | Circular path |
| D. | Elliptical path |
| Answer» C. Circular path | |
| 50. |
A single-mode optical fiber has a beat length of 8 cm at 1300 mn. The value of birefringence Bf will be nearly |
| A. | 1.6 x 10-5 |
| B. | 2.7 x 10-5 |
| C. | 3.2 x 10-5 |
| D. | 4.9 x 10-5 |
| Answer» B. 2.7 x 10-5 | |