Question

Which type of wavefront is formed when distance between light source and slit is infinite, whether the source is point-size or linear?​

Answer 1

Explanation:

plane wavefront

If distance is infinite the source is linear

Answer 2

Diverging spherical wavefront

Explanation:

• Rays that propagate closer to the optical axis are said to be converging, whereas those that propagate away from the axis are said to be diverging.
• Because these imaginary rays are always perpendicular to the light's wavefront, the light's vergence is proportional to the radii of curvature of the wavefronts.
• The term wavefront refers to fields that fluctuate sinusoidally in time with a single temporal frequency at each place.
• Wave fronts typically move with the passage of time.
• Case (A) - Light diverging from a point source: As light diverges from a point source in all directions, the point source produces the spherical wavefront.
• Case (B): Light emerging from a convex lens when a point source is positioned at its focus: In the case of light coming from a convex lens when a point source is placed at its focus, the wavefront shape is a plane. Parallel grids make up the plane wavefront.
• Case (C): The portion of a distant star's wavefront that is caught by the earth: The fraction of the wavefront of light from a distant star caught by the earth is a plane wavefront because a small area on the surface of a huge sphere is nearly planar.
• Note that at a great distance from a small source in a uniform medium, the fronts are little sections of a sphere with a very large radius and can be thought of as planes.
• The sun's light has a plane wavefront when it reaches the earth.