A ground receiver station is receiving a signal at 5 MHz, transmitted from a ground transmitter at a distance of 200 km. Considering the surface wave propagation, what is the approximate height of the transmitting antenna required for efficient communication if the earth's radius is 6400 km?
96 m
192 m
384 m
768 m
Related Questions
The population inversion necessary for laser action used in solid state lasers is
Electrical discharge
Inelastic atom-atom collisions
Direct conversion
Optical pumping
In ruby laser, the stimulated emission is due to transition from
Ground state to excited state
Metastable state to ground state
Excited state to metastable state
Ground state to metastable state
The population inversion in helium-neon laser is produced by
Photon excitation
Electron excitation
Inelastic atomic collisions
Chemical reaction
In ruby laser, the stimulated emission is due to transition from
Ground state to excited state
Metastable state to ground state
Excited state to metastable state
Excited state to ground state
A laser beam is used for carrying out surgery because it
Is highly monochromatic
Is highly coherent
Is highly directional
Can be sharply focused
A laser is a coherent source it contains
Many wavelength
Uncoordinated waves of particular wavelength
Coordinated waves of many wavelength
Coordinated waves of particular wavelength
Which of the following is not the main characteristic of laser beam?
Monochromatic
Directional
Coherent
Divergence
A laser device produces amplification in the
Active Medium
Reflective Cavity
Output Coupler
Pumping Source
The population inversion in helium-neon laser is produced by
Direct excitation of neon atoms by electrical discharge.
Absorption of photons by neon atoms.
Inelastic collisions of helium atoms with neon atoms.
Thermal excitation of neon atoms.
A laser beam is used for carrying out surgery because it
Is highly monochromatic
Is highly coherent
Is highly directional
Can be sharply focused
