The frequency from 3 to 30MHz is known as:
A) Audio band.
B) Medium frequency band.
C) Very high frequency band.
D) High frequency band.

Hint:Frequency is defined as the number of oscillations made per second. The frequency is mathematically defined as one upon the time period of any wave. Time period is defined as the time taken by the wave to complete one oscillation.

Complete answer:
It is given in the problem that the frequency from 3 to 30MHz and we need to tell in which group this frequency band lies.

The classification of the frequency band is done by the International Telecommunication Union. The international telecommunication union is a specialized agency of all the nations and deals with all the matters with the matter of information and telecommunication.

The classification of the band is given as:
A) The frequency ranging from 3Hz-30Hz comes under an extremely low frequency band.
B) The frequency ranging from 30Hz-300Hz comes under a super low frequency band.
C) The frequency ranging from 300Hz-3KHZ comes under ultra low frequency low band.
D) The frequency ranging from 300-3000 KHz comes under medium frequency band.
E) The frequency ranging from 3-30MHz comes under a high frequency band.
F) The frequency ranging from 30-300MHz comes under a very high frequency band.
G) The frequency ranging from 300-3000MHz comes under ultra-high frequency band.

The given frequency range 3 to 30MHz falls under the range of very high frequency bands.

The correct answer for this problem is option C.

Note: It is important for students to remember the classification of the frequency as it is very useful in solving these types of problems. The concept of frequency is very important in the field of wave nature of the electromagnetic wave.