Wave Equation

The given wave function is The general form of the wave function for a matter wave is , where are the wave vectors in the , , and directions, and is the angular frequency. Comparing the exponents of both wave functions, we find: - ,
- ,
- .
The direction of propagation of the matter wave is given by the unit vector along the wave vector , which is normalized as: Substituting the values of , we get: Thus, the unit vector representing the direction of propagation is , which corresponds to option (A).