Challenge 1: Building a Polished, Mirror-Like Chrome Material — Solution Walkthrough

The answer:

Per this chapter's own comparison table, a low Roughness value combined
with Metallic set to on produces a polished, mirror-like metal
appearance — exactly what chrome looks like. Low roughness produces
sharp, mirror-like reflections rather than a scattered, matte look,
and Metallic turned on gives the surface metal's own distinct way of
reflecting colored light.

Why both properties need to be set this way together:

Setting only Metallic on with a high Roughness value would instead
produce a brushed or rough metal look, per this chapter's own table —
still a metal, but not the polished, reflective chrome finish being
asked for here. Both the low roughness and the metallic property are
needed together to get specifically a mirror-like result.

Why this connects to this chapter's own broader point:

Per this chapter's own material, these two properties alone define
most of what makes a rendered surface read as a specific real-world
material — chrome is a clean, direct example of exactly that
principle in action.

WHY THIS WORKS AS AN ANSWER
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This exercise checks that a mirror-like chrome look is correctly
matched to low Roughness plus Metallic on, using this chapter's own
comparison table.