Regarding industrial light sensors (photoelectric sensors), which statement is accurate about their practical use and availability?

Introduction / Context:
Photoelectric sensors detect objects or positions using emitted and received light. They are staples in automation for counting, presence sensing, and position detection. This question distinguishes true, practical statements from absolute but inaccurate claims about their limitations and sources.

Given Data / Assumptions:

• Common types: through-beam, retro-reflective, diffuse, and fiber-optic variants.
• Light sources include infrared, visible red, and laser diodes.
• Environmental challenges include ambient light, dust, and vibration.

Concept / Approach:
Manufacturers provide many housings and mounting options (cylindrical, rectangular, miniatures, fork types, angled brackets) to suit mechanical constraints. Photoelectric sensors can indeed act as “electronic limit switches.” Claims that they never use infrared or always work in direct sunlight unconditionally are false; many use IR, and direct sun can saturate receivers unless mitigated (filters/shields/modulation).

Step-by-Step Solution:
1) Evaluate use as limit switches: possible and common—so statement A is false. 2) Evaluate mounting styles: extensive variety exists—statement B is true. 3) Evaluate direct sunlight: not a blanket guarantee; sunlight can overwhelm sensors—statement C is false as stated. 4) Evaluate IR usage: many sensors are IR-based—statement D is false. 5) Therefore, B is the accurate choice.

Verification / Alternative check:
Vendor catalogs show multiple mechanical formats and IR emitters with optical filtering and modulation to reject ambient light, confirming the reasoning.

Why Other Options Are Wrong:
Option A: Photoeyes frequently replace mechanical limit switches.
Option C: Direct sunlight often requires countermeasures; not “works regardless.”
Option D: Infrared is a very common emitter choice.
Option E: Not applicable since B is correct.

Common Pitfalls:
Ignoring ambient-light immunity specs and failing to use reflectors or shielding can cause false trips; mounting choice helps mitigate these issues.

Final Answer:
Come in a wide variety of mounting styles