Home / ECE / Electromagnetic Field Thoery :: section-14

ECE :: Electromagnetic Field Thoery

  1. Tropospheric scatter propagation is not subject to any fading.

  2. A.

     True

    B.

     False


  3. A square corner reflector is used in which of the following?

  4. A.

     TV broadcast

    B.

     Point-to-point communication

    C.

     Radio astronomy

    D.

     All of the above


  5. In an impedance smith chart, a clockwise movement along a constant resistance circle gives rise to

  6. A.

     Decrease in the value of reactance

    B.

     An increase in the value of reactance

    C.

     No change in the reactance value

    D.

     No change in the impedance value


  7. In case of surface waves the field strength at a point is directly proportional to

  8. A.

     Antenna height

    B.

     Wave frequency

    C.

     Current of the antenna

    D.

     Distance of the point from the antenna


  9. The radiation pattern of Hertzian dipole in the plane perpendicular to dipole is a

  10. A.

     Null

    B.

     Circle

    C.

     Figure of eight

    D.

     None of the above


  11. In a perfect conductor the incident and reflected wave combine to produce

  12. A.

     A stronger incident wave

    B.

     A stronger reflected wave

    C.

     A standing wave which is not progressing

    D.

     None of the above


  13. It is best to use for coupling a coaxial line to a parallel wire transmission line.

  14. A.

     Directional Coupler

    B.

     Balun

    C.

     Slotted line

    D.

     Tee


  15. In H-plane metal plate lens the travelling wave front is

  16. A.

     Totally retarded

    B.

     Retarded

    C.

     Accelerated

    D.

     Neither accelerated nor retarded


  17. Which of the following is multiband HF receiving antenna?

  18. A.

     Square loop

    B.

     Log-periodic

    C.

     Conical horn

    D.

     Folded dipole


  19. An open wire transmission line having a characteristic impedance of 600 ohms is terminated by a resistive load of 900 O. The standing wave ratio will be

  20. A.

     1.5

    B.

     2.5

    C.

     3.5

    D.

     4.5