Ncert Exercises & Solutions

What is the shape of the wavefront on earth for sunlight?

Hint: The Sun is at a very large distance from the Earth.

We know that the sun is at a very large distance from the earth. Assuming sun as spherical. lt can be considered as point source situated at infinity. Due to the large distance, the radius of the wavefront can be considered as large (infinity) and hence, wavefront is almost plane.