For a travelling harmonic wave \(\mathrm{y}(\mathrm{x},\mathrm{t})=2.0\cos 2\pi (10\mathrm{t}-0.0080\mathrm{x}+0.35)\), …

For a travelling harmonic wave \(\mathrm{y}(\mathrm{x},\mathrm{t})=2.0\cos 2\pi (10\mathrm{t}-0.0080\mathrm{x}+0.35)\), where x and y are in cm and t in s. The phase difference between oscillatory motion of two points separated by a distance of 0.5 m is :