Amplitude refers to the maximum change of a variable from its mean value (when the variable oscillates about this mean value). In to and fro motion of a particle about a mean position, it is the maximum displacement from its mean position. Similarly, amplitudes are defined for periodic pressure variations, periodic current or voltage variations, periodic variations in electric or magnetic fields etc.
There is no particular formula for amplitude. It’s available from the equations or the graphical representations of such variations. If y = A sin ωtampere. What is the peak value of the current? Options: (a) 5 A (b) 2.5 A (c) 4.33 A (d) 7 A Answer: (a)