A progressive wave is travelling. How far apart are 2 points (i.e. situated at minimum distance) 60 degree out of phase?Wave Frequency is 500 Hz...

We know that  frequency *wavelength = volcity.
Or

n*L = v.  But frequency n = 500  and  v =
360m/s,

Therfore wave length L = v/n = (360)/500 = 0.72
m.

Therefore in a cycle (one full osciilation of ) 360
degree the wave progress 0.72m. The points onthe a wave with aphase difference of 60
degree are at a distance  of (60/360)*(0.72m) = 0.12 meter
apart.