Electronic Engineering MCQ Question Papers: ENTC, IT Interview Placement

Subject: Electromagnetic and Transmission Lines 5

**Part 5: List for questions and answers of Electro Magnetics & Transmission Line**

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**Q1. The phenomenon of work done while moving a point charge in presence of an electric ****field is independent of _______**

**a) Position**

**b) Force**

**c) Path**

**d) All of the above**

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**Q2. During the movement of a charge, potential energy undergoes _________**

**a) Expansion**

**b) Compression**

**c) Radiation**

**d) Reflection**

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**Q3. During the representation of relationship between flux density and electric field density, ****what would be the value of relative permittivity for air medium?**

**a) 0**

**b) 1**

**c) 8.85 x 10^-12 F/m**

**d) 8**

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**Q4. If a negative charge is absent corresponding to Faraday’s experiment of concentric ****spheres, then where do the flux lines show termination?**

**a) At zero**

**b) At unity**

**c) At infinity**

**d) At radial field**

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**Q5. Which type of phenomenon is likely to occur, if two charges possess opposite sign?**

**a) Force of attraction**

**b) Force of repulsion**

**c) Force of stability**

**d) Force of equality**

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**Q6. According to coulomb’s law, what do the force between two point charges proportional ****to?**

**a) Addition of charges**

**b) Difference of charges**

**c) Product of charges**

**d) Integration of charges **

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**Q7. In accordance to Newton’s law, if two bodies m1 & m2 are separated by a distance R,**

**then what would be the value of gravitational force between them?**

**a) m1m2 G/R^2**

**b) m1m2/R^2**

**c) m1m2 G2/R**

**d) (m1m2)^2 G/R**

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**Q8. A broadside array consisting of 200 cm wavelength with 10 half-wave dipole spacing 10 ****cm. And if each array element feeding with 1 amp. current and operating at same frequency ****then find the half power beamwidth**

**a) 4°**

**b) 2°**

**c) 10°**

**d) 15°**

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**Q9. Refractive index of glass is 1.5. Find the wavelength of a beam of light with a frequency ****of 1014 Hz in glass. Assume velocity of light is 3 x 10^8 m/sec in vacuum**

**a) 4 µm**

**b) 3 µm**

**c) 2 µm**

**d) 1 µm**

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**Q10. The function f(x – vot) represent which of the following?**

**a) A stationary wave**

**b) A wave motion in forward direction**

**c) A wave motion in reverse direction**

**d) None of the above**

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**Q11. A broadside array operating at 100 cm wavelength consist of 4 half-wave dipoles ****spaced 50 cm apart. Each element carries radio frequency current in the same phase and of ****magnitude 0.5 A. The radiated power will be**

**a) 196 W**

**b) 73 W**

**c) 36.5 W**

**d) 18.25 W **

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**Q12. A rectangular metal waveguide filled with a dielectric of relative permittivity er = 4, has ****the inside dimensions 3 x 1.2 cm, the cut off frequency for the dominant mode is**

**a) 2.5 GHz**

**b) 5 GHz**

**c) `10 GHz**

**d) 12.5 GHz**

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**Q13. Find the radiation resistance of an antenna of length ?/10 meter?**

**a) 8 O**

**b) 780 O**

**c) 7.8 O**

**d) 78 O**

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**Q14. A wave is propagated in a waveguide at frequency of 9 GHz and separation is 2 cm ****between walls find cut off wavelength for dominant mode**

**a) 4 cm**

**b) 1 cm**

**c) 2 cm**

**d) 8 cm**

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**Q15. The input impedance of short-circuited line of length l where λ /4 is less l is less than ****λ /2, is**

**a) resistive**

**b) inductive**

**c) capacitive**

**d) none of the above**

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**Q16. A wave is propagated in a waveguide at frequency of 9 GHz and separation is 2 cm ****between walls Calculate group velocity for dominant mode**

**a) 1.8 x 10^8 m/sec**

**b) 5 x 10^8 m/sec**

**c) 3 x 10^8 m/sec**

**d) 1.5 x 10^8 m/sec**

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**Q17. For F1 layer the maximum ionic density is 2.3 x 10^4 electrons per cc. The critical ****frequency for this layer will be**

**a) 1.36 MHz**

**b) 13.6 MHz**

**c) 136 MHz**

**d) 1360 MHz **

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**Q18. A hollow rectangular waveguide has dimensions a = 2b. Calculate the amount of attenuation, if the frequency is 3 GHz, and b = 1 cm**

**a) 49**

**b) 47.33**

**c) 50.33**

**d) 50**

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**Q19. Calculate the directivity of an antenna for ?E = 30°, ?H = 60**

**a) 46**

**b) 23**

**c) 50**

**d) 100**

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**Q20. The phase angle corresponding to ?/4 in a standing-wave pattern is**

**a) 30°**

**b) 90°**

**c) 135°**

**d) 180° **

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**Part 5: List for questions and answers of Electro Magnetics & Transmission Line**

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**Q1. Answer: c**

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**Q2. Answer: a**

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**Q3. Answer: b**

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**Q4. Answer: c**

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**Q5. Answer: a**

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**Q6. Answer: c**

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**Q7. Answer: c**

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**Q8. Answer: b**

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**Q9. Answer: c**

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**Q10. Answer: b**

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**Q11. Answer: a**

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**Q12. Answer: b**

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**Q13. Answer: c**

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**Q14. Answer: a**

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**Q15. Answer: c**

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**Q16. Answer: a**

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**Q17. Answer: b**

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**Q18. Answer: b**

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**Q19. Answer: b**

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**Q20. Answer: b**