Measurement errors are deviations from the true value of a measurement due to various factors. They can be categorized based on their sources into three main types:
Gross Errors
Gross errors occur due to human oversight and mistakes in reading, recording, or interpreting data. These are the most common types of errors and can be minimized through careful measurement and proper techniques.
Examples of Gross Errors:
- Misreading the scale of an instrument (e.g., reading 23 as 28)
- Recording incorrect values
- Calculation mistakes
Ways to Reduce Gross Errors:
- Take careful readings and record data accurately.
- Increase the number of observers taking readings at different points and use the average value.
Random Errors
Random errors occur unpredictably due to fluctuations in experimental conditions such as temperature changes, voltage variations, or mechanical vibrations. These errors cause variations in repeated measurements.
Examples of Random Errors:
- Observer inconsistency in repeated measurements
- Unpredictable environmental changes affecting measurements
How to Reduce Random Errors:
- Take multiple readings and use statistical methods to determine the average and standard deviation.
- Use precision instruments with fine calibration.
Systematic Errors
Systematic errors are consistent and repeatable inaccuracies that arise from known sources. They can be classified into three types:
a) Environmental Errors
These occur due to external conditions such as temperature, pressure, humidity, and electromagnetic fields.
Example: Measuring body temperature in a room where the air conditioner stops working, leading to increased temperature readings.
b) Observational Errors
These arise due to human bias, incorrect apparatus setup, or carelessness in observation. Parallax errors are a common type of observational error.
Example: Taking a reading from an angle rather than directly in front of the scale.
c) Instrumental Errors
These errors occur due to faulty instrument construction, calibration errors, or wear and tear of instruments. Zero errors in Vernier calipers and screw gauges are common examples.
Example: A weighing scale that does not reset to zero before measurement.
Instrumental Errors Arise Due To:
- Inherent constraints of devices
- Misuse of apparatus
- Loading effects
Question-Answer Format for Exams (JEE, NEET, CBSE Class 11)
Q1: What are the three main types of errors in measurement?
Answer:
- Gross Errors
- Random Errors
- Systematic Errors
Q2: How can we reduce gross errors in measurement?
Answer: Gross errors can be minimized by careful reading and recording of data, and by increasing the number of experimenters taking independent measurements.
Q3: What is a parallax error?
Answer: A parallax error occurs when the observer views a scale from an angle rather than directly, leading to incorrect readings.
Q4: Give an example of an environmental error.
Answer: Measuring body temperature in a room where the air conditioning fails, affecting the accuracy of the reading.
Q5: What are zero errors?
Answer: Zero errors occur when an instrument does not start from zero, leading to consistent measurement inaccuracies.
MCQs with Answers and Explanations
1. Which of the following is a type of systematic error?
a) Human error
b) Instrumental error
c) Parallax error
d) Both b and c
Answer: d) Both b and c
Explanation: Instrumental and parallax errors are categorized under systematic errors because they are predictable and repeatable.
2. How can random errors be reduced?
a) By repeating the experiment multiple times
b) By taking a single measurement
c) By avoiding zero errors
d) None of the above
Answer: a) By repeating the experiment multiple times
Explanation: Random errors can be minimized by taking multiple readings and calculating the average.
3. A weighing scale that does not reset to zero before measurement is an example of:
a) Gross error
b) Instrumental error
c) Observational error
d) Environmental error
Answer: b) Instrumental error
Explanation: This is due to a fault in the calibration of the instrument.
Do You Know?
- Systematic errors can be corrected through proper calibration of instruments.
- Random errors can never be completely eliminated but can be minimized through statistical analysis.
- Gross errors often occur due to lack of experience in handling instruments.
Worksheet on Types of Errors
1. Fill in the blanks:
a) Errors in measurement can be classified into ____, ____, and ____ errors.
b) ____ errors occur due to human mistakes in recording readings.
c) Errors arising from the environment are called ____ errors.
2. Answer the following questions:
a) How can instrumental errors be minimized?
b) Explain the impact of observational errors in measurements.
Test Paper (10 Marks Distribution)
- Define systematic errors and explain their types. (3 marks)
- What are the causes of random errors? (2 marks)
- Differentiate between gross errors and systematic errors. (2 marks)
- Explain the role of environmental errors in measurements. (3 marks)
Important Points for Quick Revision
- Measurement errors can be gross, random, or systematic.
- Gross errors occur due to human mistakes in observation or recording.
- Random errors arise unpredictably due to experimental fluctuations.
- Systematic errors are consistent and can be divided into environmental, observational, and instrumental errors.
- Reducing errors involves proper calibration, repeated observations, and careful handling of instruments.
Test Your Knowledge (Quiz)
Buy complete study material at:
https://publishers.anandclasses.co.in/
Proprietor: NIRMAL ANAND Educations
Written by: Neeraj Anand
Published by: Anand Technical Publishers Under Anand Classes
Contact: +91-9463138669
Email: anandclasses1996@gmail.com
