A Beam of X-Rays of Wavelength 0

Multiple Choice

A beam of x-rays of wavelength 0.20 nm is diffracted by a set of planes in a crystal whose separation is 3.1 *10^-8 cm. The smallest angle between the beam and the crystal planes for which a reflection occurs is:

A) 0.70 rad
B) 0.33 rad
C) 0.033 rad
D) 0.066 rad
E) no such angle exists