Antenna and Wave Propagation 3

Electronic Engineering MCQ Question Papers: ENTC, IT Interview Placement

Subject: Antenna and Wave Propagation 3

Part 3: List for questions and answers of Antenna & wave Propagation

Q1. 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

Q2. What is the nature of current distribution over the small dipoles?

a) Spherical

b) Rectangular

c) Triangular

d) Square

Q3. Which term is regarded as an inductive field as it is predictable from Biot Savart law and considered to be of prime importance at near field or the distance close to current element?

a) 1/r

b) 1/r^2

c) 1/r^3

d) 1/r^4

Q4. Dipole antenna is symmetrical in nature where the two ends are at equal potentials with respect to _____point

a) Initial

b) Eventual

c) Mid

d) None of the above

Q5. If a half-wave dipole operates at 300 MHz with  λ  = 0.5m and D0 = 1.643, what will be its effective area?

a) 0.032 m^2

b) 0.047 m^2

c) 0.65 m^2

d) 0.99 m^2

Q6. In the solutions of inhomogeneous vector potential wave equation, which component exists if the source is at origin and the points are removed from the source (Jz = 0)?

a) Inward

b) Outward

c) Both a and b

d) None of the above

Q7. In retarded potentials, what factor of time delay is generally introduced in A and V equations?

a) R + c

b) R – c

c) R/c

d) R x c

Q8. The vector magnetic potential shows the inverse relationship with its ____

a) Source

b) Distance of point from the source (R)

c) Both a and b

d) None of the above

Q9. According to the geometry, how many sterdians are present in a full sphere?

a) p/2

b) p

c) 2 p

d) 4 p

Q10. Which type of ground wave travels over the earth surface by acquiring direct path through air from transmitting to receiving antennas?

a) Surface wave

b) Space wave

c) Both a and b

d) None of the above

Q11. In an electrical circuit, which nature of impedance causes the current and voltages in phase?

a) Reactive

b) Resistive

c) Capacitive

d) Inductive

Q12. If the magnetic field component of a plane wave in a lossless dielectric is  H = 50 sin (2π x 106 t – 6x) az  mA/m   , what will be the wave velocity?

a) 1.047 x 106 m/s

b) 1.257 x 106 m/s

c) 2.50 x 106 m/s

d) 3 x 106 m/s

Q13. Which equations are regarded as wave equations in frequency domain for lossless media?

a) Maxwell’s

b) Lorentz

c) Helmholtz

d) Poisson’s

Q14. Which among the following exhibits perpendicular nature in TEM wave?

a) Electric field

b) Magnetic field

c) Direction of propagation

d) All of the above

Q15. In ungrounded antennas, if an excitation is applied directly across the base insulator, then on which factor/s would the voltage across the insulator depend?

a) Power delivered to antenna

b) Power factor of impedance

c) Both a and b

d) None of the above

Q16. If the tower antenna is not grounded, which method of excitation is/are applicable for it?

a) Series

b) Shunt

c) Both a and b

d) None of the above

Q17. For which band/s is the space wave propagation suitable over 30 MHz?

a) VHF

b) SHF

c) UHF

d) All of the above

Q18. Which mode of propagation is adopted in HF antennas?

a) Ionospheric

b) Ground wave

c) Tropospheric

d) All of the above

Q19. What is the possible range of height for the occurrence of sporadic E-region with

respect to normal E-region?

a) 20 km to 50 km

b) 45 km to 85 km

c) 90 km to 130 km

d) 140km to 200 km

Q20. In broadside array, all the elements in the array should have similar _______excitation along with similar amplitude excitation for maximum radiation

a) Phase

b) Frequency

c) Current

d) Voltage

Part 3: List for questions and answers of Antenna & wave Propagation