Define the wavefront of light.

What is the shape of the wavefront in each of the following cases: The portion of the wavefront of light from a distant star intercepted by the Earth.

Define the term resolving power of an astronomical telescope.How does it get affeted on increasing the wavelength of light used?

Define the term 'wavefront'.

Define wavefront and a ray.

What is meant by a wavefront?What is the shape of the wavefront of a beam of parallel rays?