What is the phase difference between particles being on either side of a node?

What is the phase diffrence between the particle 1 and 2 located as shown in

In the Q. 89 the phase difference between two points on opposite sides of an antinode with a separtion of 1 cm between then is:

What is the phase difference between two successive crests in the wave

What is the difference between a beta particle and electron?

What is the phase difference between any two points on a wavefront ?

The phase difference between particle velocity and wave velocity is

What is the phase difference between any two points on a spherical wavefront?