Select all the correct statements.

In a linear absorption process, the energy starts to be absorbed as soon as the light penetrates in the material.

Metal forming techniques of parts such as folding or deep-drawing intrinsically makes them more brittle, i.e., their plasticity domain is reduced.

Select all the INCORRECT statements!

In laser processing, so-called "voxel" corresponds to the volume where the light beam is sufficiently focused to actually reach the desired energy level. It is typically an ellipsoid extending over the depth of focus and located at the beam waist. We can represent it as follows:

Suppose that we need to obtain a machining voxel of  um diameter and  um height. We are working with a Gaussian beam (see Lecture 3, slide 54 in the final version of the slides). Note that the depth of focus is two times the Rayleigh length.

Select the right analytical expression giving the wavelength that one could use to reach these dimensions as a function of and .

As seen in class, lasers can be used as a tool for transforming cubes into almost perfect spheres at the microscale, as illustrated below. In this process, the volume of material is ideally unchanged after processing.

Select all the correct statements.

We have discussed the effect of multiple methods to increase the yield strength of metals, like for instance in copper:

Which statement is WRONG among the following?