The process of superimposing signal frequency (i.e. audio wave) on the carrier wave is known as :
Transmission
Reception
Modulation
Detection
Long distance short-wave radio broadcasting uses :
Ground wave
Ionospheric wave
Direct wave
Sky wave
The radio waves of frequency 300 MHz to 3000 MHz belong to :
High frequency band
Very high frequency band
Ultra high frequency band
Super high frequency band
The electromagnetic waves of frequency 2 MHz to 30 MHz are :
In ground wave propagation
In sky wave propagation
In microwave propagation
In satellite communication
A laser is a coherent source because it contains :
Many wavelengths
Uncoordinated wave of a particular wavelength
Coordinated wave of many wavelengths
Coordinated waves of a particular wavelength
The attenuation in optical fibre is mainly due to :
Absorption
Scattering
Neither absorption nor scattering
Both A and B
The maximum distance upto which TV transmission from a TV tower of height h can be received is proportional to :
h1/2
h
h3/2
h2
Laser beams are used to measure long distances because :
They are monochromatic
They are highly polarised
They are coherent
They have high degree of parallelism
Which of the following is the disadvantage of FM over AM?
Larger band width requirement
Larger noise
Higher modulation power
Low efficiency
An antenna is a device :
That converts electromagnetic energy into radio frequency signal
That converts radio frequency signal into electromagnetic energy
That converts guided electromagnetic waves into free space electromagnetic waves and vice-versa
None of the above