Question

Error in measurement caused by factors which vary with measurements is _________.

• A. Crude error
• B. Reagent error
• C. Random error
• D. Operational error

Hint:

While systematic errors affect the accuracy of a measurement (how close it is to the true value), random errors affect the precision of the measurement (how reproducible the results are).

Answer 1

The Correct Option is C

Step 1: Understanding the Concept:
Every scientific measurement contains some degree of uncertainty, known as error.
Errors are classified into systematic (determinate) errors and random (indeterminate) errors based on their predictability and behavior.

Step 3: Detailed Explanation:
Let us analyze the types of errors in scientific measurements:
1. Random Errors (C): These are caused by unpredictable, uncontrollable fluctuations in environmental conditions, instrument sensitivity, or human observation during measurement.
Because these factors vary randomly from one measurement to the next, the resulting errors vary in both magnitude and direction (either positive or negative).
Random errors cannot be eliminated, but their effect can be minimized by taking multiple replicate measurements and calculating the mean.
2. Systematic Errors (such as Reagent error or Operational error): These have a constant, predictable value and direction under the same conditions.
They are caused by flawed equipment, impure reagents, or consistent observer bias, and can be identified and corrected.
3. Crude Errors (A): These are large, obvious mistakes caused by human negligence or equipment failure (e.g., misreading a scale or transposing numbers), which can be avoided.
Therefore, errors caused by factors that vary randomly with each measurement are classified as random errors.

Step 4: Final Answer:
The error caused by variable factors is Random error, corresponding to option (C).