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

CHAPTER 6
PHYSICAL
OPTICS
•
6-1. Interference of Light
763. Two light waves are superposed in a certain section of
space and extinguish each other. Does this mean that a quantity
of light is converted into other kinds of energy?
764. Two coherent sources of light 8 1
and 8, are at a distance 1
from each other. A screen is placed at a distance D ~ l from
the sources (Fig. 253). Find the distance between adjacent interference
bands. near the middle of the screen (point A) if the
sources send light with a wavelength 'A.
765. Two flat mirrors form an angle close to 180 0 (Fig. 254).
A source of light S is placed at equal distances b from the
mirrors. Find the interval between adjacent interference bands
on screen MN at a distance OA = a from the point of intersection
of the mirrors. The length of the light wave is known and
equal to 'A. Shield C does not allow the light to pass directly
from the source to the screen.
766. Lloyd's interference experiment consisted in obtaining
on a screen a pattern from source S and from its virtual image S'
in mirror AO (Fig. 255). How will the interference pattern
obtained from sources S and Sf differ from the pattern considered
in Problem 764?
t ·oS;
I .....CE-------.D -----~...A
l ..sz
Fig. 253