Question

During the detection of the cones by the thin strip of film which one of the following statements is appropriate for the cones and the films?

(a) Cones are parallel to the strip of the films

(b) Cones are perpendicular to the strip of the films

(c) Cones intersects the strip of the films

(d) Cones are vertically placed over the strip of the film

The question was posed to me in semester exam.

My query is from The X-ray Diffraction Experiment in section X-Ray Diffraction of Solid State Chemistry

Answer 1

Correct choice is (c) Cones intersects the strip of the films

The explanation is: In the powder method, the cones are detected by a thin strip of film wrapped around the sample, each cone intersects the film as two short arcs which are symmetrical about the two holes in the film(these allow entry and exit of an incident and undiffracted beams).