When the prefix ‘kilo’ is added to a unit, the unit increases by a factor of ____.
Decibel (dB) is a unit of loudness of sound. It is defined in a manner such that when the amplitude of the sound is multiplied by a factor of √10, the decibel level increases by 10 units. Loud music of 70dB is being played at a function. To reduce the loudness to a level of 30dB, the amplitude of the instrument playing music has to be reduced by a factor of: