|
Let us consider two rays of monochromatic light (wavelength λ), one which originates from slit 1 and the other from slit 2, which interfere at a certain position P on the screen. The distance of slit 1 to P is denoted by  1,
the distance of slit 2
to P by 2.
Let the phase of the light in the slits be given by φ0. We assume that the phases of light rays in the two slits are equal (coherent light). Let, furthermore, the phases of the two rays at P be represented by respectively φ1 and φ2. Then (notice that φ1<φ0 and φ2<φ0) 1
/ λ
and
φ0
- φ2
= 2π2
/ λ
Hence 1
- 2
) / λ
|