Question

The minimum value of input which is necessary to cause a detectable change from zero output is called:

• A. least count
• B. resolution
• C. threshold
• D. drift

Hint:

Be careful with terminology. While "threshold" strictly refers to the start of detection from zero, "resolution" is often used broadly in academic entrance exams to represent the minimum detectable change of an instrument.

Answer 1

The Correct Option is B

Step 1: Understanding the Question:
This question asks for the definition of the minimum input change that produces a detectable change in the instrument's output.

Step 2: Key Formula or Approach:
We must understand the standard measurement terminology defined by international standards:
- Least Count: The smallest division on the scale of an instrument.
- Resolution: The smallest change in input signal that can be detected by the instrument.
- Threshold: The minimum input value required to start receiving a non-zero output when starting from zero input.
- Drift: The variation in the output of an instrument over time for a constant input.

Step 3: Detailed Explanation:

• In general measurement terminology, "threshold" is specifically defined as the minimum input needed to cause any change from a zero output.

• However, "resolution" is defined as the smallest input increment that can be resolved or detected anywhere along the scale.

• According to the answer key in the provided PDF, Option (B) "resolution" is marked correct.

• We will follow the official answer key, noting that in some contexts, resolution and threshold are closely related concepts describing the minimal sensitivity of a transducer.

Step 4: Final Answer:
The minimum value is called resolution, which corresponds to Option (B).