Electromagnetic and Transmission Lines 3

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Electronic Engineering MCQ Question Papers: ENTC, IT Interview Placement

Subject:  Electromagnetic and Transmission Lines 3

Part 3: List for questions and answers of Electro Magnetics & Transmission Line


Q1. In a magnetic flux density, the total magnetic lines of force crossing a unit area in plane to the direction of flux are at _______

a) Acute angles

b) Obtuse angles

c) Right angles

d) None of the above


Q2. Consider the statements related to the case of boundary between two conductors. Which among them is/are incorrect?

a) Electric field must be parallel to the surface of good conductor

b) Static electric field inside the conductor is always zero

c) Surface of conductor is always an equipotential surface

d) All of the above


Q3. Which among the following is not a boundary condition between the conductor and the dielectric (ε = ε0 εr) ?

a) Et = 0

b) Dt = 1

c) DN = ?s

d) EN  = ρs / ε0εr 


Q4. In the equation DN = ?s, the normal component of electric flux density is equal to __________

a) Surface charge density

b) Volume charge density

c) Line charge density

d) Surface area


Q5. Which among the following equation shows the correct relationship between electric field intensity and electric flux density?

a) Dt = e0 Et

b) Et = e0 Dt

c) Dt = Et/e0

d) (Dt + Et) = 1 


Q6. Which among the following elements is/are not possessed by steady state current?

a) Source

b) Sink

c) Both a and b

d) None of the above


Q7. Rate of decrease in charge for volume ‘V’ bounded by a surface is equal to ______

a) Incoming current rate

b) Outgoing current rate

c) Stable current rate

d) None of the above


Q8. Which law/principle of conservation provides the basis for the continuity equation of current?

a) Mass action

b) Energy

c) Charge

d) Momentum


Q9. If the motion of charge (Q) is against the electric field with an additional requirement of external force, then what would be the nature of work done?

a) Positive

b) Negative

c) Null (zero)

d) Infinity


Q10. Work done becomes zero, if the selected path is located in _______ direction to electric field intensity (E)

a) Parallel

b) Perpendicular

c) Opposite

d) Adjacent


Q11. Whenever a wave is incident on a perfect conductor then the reflection coefficient is

a) 1

b) 0

c) 1 is less than 180°

d) depend upon η1, η2 


Q12. When a wave is incident from the more dense into a less dense medium at an angle equal to or exceeding the critical angle, the wave suffers total internal __________

a) reflection

b) refraction

c) transmission

d) none of the above


Q13. Radiation intensity in a given direction is the

a) energy radiated per square metre

b) power radiated per square metre

c) power radiated per unit solid angle in that direction

d) none of the above


Q14. If ωe is the displacement current factor and s is conduction current density factor then which of the following statements is incorrect?

a) For a lossless dielectric s = 0

b) For an imperfect dielectric s = 0

c) For a dielectric ωε  >> s

d) For a semiconductor ωε  = s


Q15. Parabolic and lens antenna used at

a) microwave frequency

b) medium frequency

c) low frequency

d) high frequency


Q16. Which of the following statement regarding waveguides is incorrect?

a) At waveguide can be coupled to a coaxial cable

b) At frequencies below the cut off value the wave progresses across the waveguide after total reflections

c) Waveguides are usually air filled hollow conducting metallic tubes for transmitting UHF and microwaves

d) Waveguides can handle large power at UHF and microwaves


Q17. The potential that appears at a point in space due to the current which caused it is

called potential

a) accelerating

b) retardation

c) oscillating

d) lagging the current 


Q18. Which of the following statement is false?

a) A half-wave dipole is a resonant antenna

b) A horizontal antenna transmits radio signal with horizontal polarization

c) The field strength of 200 mV/m will produced 200 µV of signal in an antenna 2 m long

d) All of the above


Q19. The useful magnetic flux obtainable from any closed surface is

a) unity

b) constant

c) both (a) and (b)

d) none of the above


Q20. MUF is depend upon

a) electron density of the ionospheric layer

b) 11 year sun spot cycle

c) received frequency by receiver

d) height of ionospheric layer 


Part 3: List for questions and answers of Electrom agnetic  & Transmission Line


Q1. Answer: c


Q2. Answer: a


Q3. Answer: b


Q4. Answer: a


Q5. Answer: a


Q6. Answer: d


Q7. Answer: b


Q8. Answer: b


Q9. Answer: a


Q10. Answer: b


Q11. Answer: b


Q12. Answer: b


Q13. Answer: c


Q14. Answer: b


Q15. Answer: a


Q16. Answer: a


Q17. Answer: b


Q18. Answer: c


Q19. Answer: d


Q20. Answer: c