Two point sources, A and B, produce coherent electromagnetic waves. The waves from A and B are emitted in phase and have wavelength 
as shown in the figure below.
The waves in air have a wavelength of 
. An interference pattern is detected along a line parallel to AB and at a perpendicular distance of 
from AB. The spacing between adjacent interference maxima is 
.
Calculate the separation 
of the sources A and B.
State the principal region of the electromagnetic spectrum to which the waves belong.
.
