Variable resistors (rheostats and potentiometers): The resistive track can be manufactured with a linear or a tapered (audio/log) law. Evaluate the statement.

Introduction / Context:Potentiometers and rheostats are used for volume controls, sensor calibration, and bias adjustments. Their mechanical angle-to-resistance profile, called taper, determines how resistance changes with rotation or slider position.

Given Data / Assumptions:

• Two common tapers: linear and logarithmic (audio).
• Applications differ: instrumentation versus audio perception.
• Construction may be carbon film, cermet, or wirewound.

Concept / Approach:A linear taper produces resistance proportional to travel, ideal for measurement and control systems needing uniform response. A tapered (log/audio) profile matches human loudness perception; equal angular increments produce perceived equal loudness steps. Other specialty tapers (reverse log, S-curve) exist but are less common.

Step-by-Step Solution:

Verification / Alternative check:Datasheets identify parts as “A” (log/audio) or “B” (linear), confirming the industry practice of offering both tapers.

Why Other Options Are Wrong:Incorrect: Conflicts with ubiquitous availability and labeling of linear and audio tapers.

Common Pitfalls:Assuming taper letters are universal across regions (some standards swap A/B). Confusing taper with total resistance value or power rating.

Final Answer:Correct