Bukhovtsev-et-al-Problems-in-Elementary-Physics

CHAPTER 6
PHYSICAL
OPTICS
6-1. Interference of Light
763. NOt it does not. The presence of Illumination minima on the interference
pattern means that no quantity of light enters the given section of
space. /
764. The maximum illumination will be observed at an arbitrary point of
the screen C (Fig. 550) if the difference of the paths d l-d1 =kA, where
k=O, 1, 2, ... is an integer.
According to the Pythagorean theorem,
d: = DI+( hk +;r
d~=D'+( hk - ;r
whence
d:-d~=(d,+dl)
(d,-dt)=2hlc'
In accordance with ~he initial conditlon d, +d t ~ 2D. Therefore, d, -d 1 ==
= k). ~ 2:~' . The distance tothe k-th light band from the centre of the screen is
h,,-= k~D • The distance between the bands is Ah=hk+l-hk=).f .
785. The distance between Interference bands is Ah=~ (see Problem 764).
In our case D==AB es:a+b, and 1=8 1 8, is the distance between the images
Sl and 52 of the source in the ftat mirrors (Fig. 551). The value of I can
r----------------------------
I
IIII
c
4 1 ~~~-----D -------:l~
Fig. 550