18EC2020_MOdule 1_Mock Test

The ratio of radiation intensity in a given direction from antenna to the radiation intensity over all directions is called as ________

• directivity

• radiation intensity

• gain

• radiation pattern

Radiation resistance of a Hertzian dipole of length λ/8 is ________

• 12.33

• 11.33

• 10.33

• 9.33

Radiation resistance of a half-wave dipole is ______

• 73

• 37.5

• 38.5

• 39.5

What is the Beam area for Directivity to be 1 in Steradian?

• 4π

• 2π

• 3π

• 5π

The radiation efficiency for antenna having radiation resistance 36.15Ω and loss resistance 0.85Ω is given by ________

• 0.977

• 0.799

• 0.797

• 0.997

If the length of the dipole decreases, then the radiation resistance will________

• decreases

• increases

• depends on current distribution

• not change

A yagi uda antenna is directional antenna consisting of parasitic elements

• with reflector and one or more director

• only director

• reflector

• driven elements

___________ are easy to generate and are widely used for both indoor and outdoor communications.

• Radio waves

• UV rays

• X-rays

• Gamma rays

Field intensity decreases with increasing distance, as ___________

• 1/r

• 1/r²

• 1/r³

• r

Shape of radiation pattern of antenna is independent on ________

• distance

• radius

• area

• height