Epoch is measured in Radians.
The initial phase of the oscillating particle is called epoch.
Consider a particle executing simple harmonic motion along the Y- axis. A simple harmonic oscillator oscillates about its mean position y = 0 to the maximum distance ‘a’ on both the sides which is known as the amplitude of simple harmonic oscillator.
- The displacement at any instant t is given by y = a sin (ωt+φ0).
- The argument of the sine function (ωt+φ0) is called as the phase of the simple harmonic oscillator at time t and φ0 is called the initial phase or epoch. ie. at t= o , φ = φ0 and this φ0 is called as the epoch. i.e. the displacement of an oscillating body at zero time.