Huygens wave theory is used

Huygens wave theory allows us to know

Huygens wave theory allows us to know

Huygens's wave theory could explain

The most important point of Huygen's wave theory is that ......

Huygens' wave theory allows us to know:

Huygen’s wave theory allows us to know :

On the basis of Huygen.s wave theory, prove Snell.s law of refraction of light. Draw a neat and labelled diagram. (Postulates of Huygen.s wave theory not required)

State one defect of Huygens wave theory.