Optical storage — how CD-R recording works Is the following statement about CD-R media correct? “A CD-R is created by heating special dye chemicals so they reflect less light than unburned areas, creating an effect equivalent to pits on a pressed CD.”

Introduction / Context:CD-R (recordable compact disc) technology differs from factory-pressed CDs. Pressed discs have physical pits and lands molded into the substrate. CD-Rs simulate this difference in reflectivity using a photosensitive dye layer altered by a recording laser. This question verifies understanding of that mechanism.

Given Data / Assumptions:

• Pressed CDs: physical pits (recessed) and lands (flat) change reflected light to encode data.
• CD-Rs: organic dye layer darkens where heated by the write laser.
• Optical pickup reads differences in reflected intensity rather than literal holes.

Concept / Approach:When the CD-R's dye is locally heated, its optical properties change (absorption/reflectance). The altered spots reflect less light, mimicking the lower-reflectivity “pit” regions on a pressed disc. The drive's photodiode sees this contrast and recovers the data stream using run-length limited coding and clock recovery.

Step-by-Step Solution:A recording laser targets dye areas along the spiral track.Heat causes a chemical/structural change, decreasing reflectivity.During playback, the reader detects reflectivity changes as pit/land transitions.Thus, burned dye regions emulate pits, confirming the statement.

Verification / Alternative check:CD-R discs often have visible color tints (cyanine, phthalocyanine, azo dyes) that darken with recording. Technical references describe reflectivity targets for Red Book compatibility.

Why Other Options Are Wrong:

• False: Would contradict the well-documented dye-based reflectivity mechanism of CD-R media.

Common Pitfalls:

• Assuming CD-Rs physically form pits; they alter dye properties to emulate pits optically.
• Confusing CD-R with CD-RW, which uses a phase-change alloy rather than an organic dye.

Final Answer:True