# Antenna and Wave Propagation 2

Electronic Engineering MCQ Question Papers: ENTC, IT Interview Placement

Subject: Antenna and Wave Propagation 2

Part 2: List for questions and answers of Antenna & wave Propagation

Q1. If the maximum electron density for F-layer in ionosphere is 4 x 10^6 electrons/cm^3, then what will be the critical frequency of EM wave for F-layer?

a) 4 MHz

b) 9 MHz

c) 18 MHz

d) 25 MHz

Q2. Which layer has the atmospheric conditions exactly opposite to that of standard atmosphere?

a) Depression layer

b) Regression layer

c) Inversion layer

d) Invasion layer

Q3. What is the direction of varying orientation of polarized surface wave at the earth surface in a wave tilt mechanism?

a) Horizontal

b) Vertical

c) Diagonal

d) Opposite

Q4. For avoiding ground losses, better is the surface conductivity, less is the __________

a) Attenuation

b) Phase velocity

c) Propagation constant

d) Tilt angle

Q5. When an electromagnetic wave travels from transmitter to receiver, which factor/s affect/s the propagation level?

a) Curvature of earth

b) Roughness of earth

c) Magnetic field of earth

d) All of the above

Q6. Linear polarization can be obtained only if the wave consists of ________

a) Ex

b) Ey

c) Both Ex and Ey and in phase

d) Both Ex and Ey and out of phase

Q7. According to depth of penetration, what is the percentage proportion of attenuated wave w.r.t its original value?

a) 17%

b) 27%

c) 37%

d) 57%

Q8. Which kind of polarization is provided by helical antennas?

a) Plane

b) zlliptical

c) Circular

d) All of the above

Q9. Why are beverage antennas not used as transmitting antenna?

c) Both a and b

d) None of the above

Q10. Which among the following is not a disadvantage of rhombic antenna?

a) Requirement of large space

b) Reduced transmission efficiency

c) Maximum radiated power along main axis

d) Wastage of power in terminating resistor

Q11. Which angle of rhombic antenna represents one half of included angle of two legs of one wire?

a) Apex angle

b) Tilt angle

c) Both a and b

d) None of the above

Q12. If the length of elements of an array is greater than λ /2, which will be the operating region of an array?

a) Transmission line region

b) Active region

c) Reflective region

d) All of the above

Q13. What kind of beam width is/are produced by Chebyshev arrays for given side lobe level (SLL)?

a) Widest

b) Narrowest

c) Both a and b

d) None of the above

Q14. If the elements of a binomial array are separated by λ /4, how many shape patterns are generated with no minor lobes?

a) 2

b) 4

c) 8

d) 16

Q15. If a linear uniform array consists of 9 isotropic elements separated by λ /4, what would be the directivity of a broadside array in dB?

a) 6.53 dB

b) 7.99 dB

c) 8.55 dB

d) 9.02 dB

Q16. What would happen if the rms value of induced emf in loop acquires an angle θ  = 90degree?

a) Wave is incident in direction of plane of the loop with induced maximum voltage

b) Wave is incident normal to plane of the loop with no induced voltage

c) Wave is incident in opposite direction of plane of the loop with minimum voltage

d) None of the above

Q17. What is the far-field position of an electric short dipole?

a) Along x-axis

b) Along y-axis

c) Along z-axis

d) Along xy plane

Q18. If the radius of loop is λ / 20 in a free space medium,what will be the radiationv resistance of 8-turn small circular loop?

a) 0.7883 ohm

b) 50.45 ohm

c) 123.17 ohm

d) 190.01 ohm

Q19. For receiving a particular frequency signal, which tuning component must be used by the loop to form a resonant circuit for tuning to that frequency?

a) Capacitor

b) Inductor

c) Resistor

d) Gyrator

Q20. What is the direction of varying orientation of polarized surface wave at the earth surface in a wave tilt mechanism?

a) Horizontal

b) Vertical

c) Diagonal

d) Opposite

Part 2: List for questions and answers of Antenna & wave Propagation