Question

In the optical grating system if α>>λ, for the constructive interference which of the following phenomenon takes place?

(a) Refraction of light

(b) Deflection continuum

(c) Diffraction continuum

(d) Refraction continuum

The question was posed to me in semester exam.

The question is from Diffraction topic in chapter X-Ray Diffraction of Solid State Chemistry

Answer 1

Correct answer is (c) Diffraction continuum

Explanation: In the optical grating system, if α>>λ individual diffraction orders (n=1, 2, 3, etc) are close together as to be unresolved and effectively, a diffraction continuum results. This is because for large values of a sinα and hence, λ must be very small.