Question

Contraction of the unit cell in the crystal occurs during which of the following phenomenon?

(a) Uniform strain is applied

(b) Uniform stress is applied

(c) Non uniform stress is applied

(d) Non uniform strain is applied

I got this question in an online interview.

I need to ask this question from Effect of Stress on a Powder Pattern in division X-Ray Diffraction of Solid State Chemistry

Answer 1

The correct answer is (b) Uniform stress is applied

Explanation: The whole powder pattern of the crystal may be shifted to lower d-spacings if the crystals are under a uniform compressive stress such that a contraction of unit cell occurs inside the crystal.