What is Fresnel's distance ?

What is Fresnel distance ? Write its formula.

What is Fresnel distance?

What is the Fresnel distance for an aperture of 3 mm and wavelength 400 nm?

What is Fresnel diffraction?

Light of wavelength 5,500 Å is illuminated on a slit. Calculate the slit width if Fresnel distance for diffraction set-up is 4 m.

Explain the importance of Fresnel distance.

For an aperture of size a illuminated by a parallel beam of light having wavelength 1, the Fresnel distance is:

Calculate Fresnel distance for aperture of 1mm using Red light of wavelength 7000Å.

For an aperture of size a illuminated by a parallel beam of light having wavelength 1, the Fresnel distance is:

Calculate Fresnel distance for aperture of 1mm using Red light of wavelength 7000Å.