**Instrumental error** is the type of error that is caused due to the faulty construction or malfunctioning of the instrument used for measurement. It leads to inaccuracies in the measurements and affects the reliability and validity of the results obtained. Here's a detailed explanation of each type of error mentioned:

**1) Instrumental error:** This type of error arises from the imperfections or limitations of the measuring instrument itself. It can occur due to various reasons such as incorrect calibration, zero error, faulty components, or improper use of the instrument. For example, if a thermometer is not calibrated properly, it may display incorrect readings, leading to instrumental error.

**2) Systematic error:** Systematic error is caused by consistent and predictable factors that affect the measurements in a specific direction. It is not related to the instrument itself but rather the experimental setup or procedure. Systematic errors can occur due to environmental factors, such as temperature variations or electromagnetic interference, or due to flaws in the experimental design. These errors are constant and can be minimized through careful calibration and standardization techniques.

**3) Personal error:** Personal error, also known as observer error, is introduced by the experimenter or the person conducting the measurements. It can occur due to limitations in the experimenter's skills, judgment, or subjective biases. Personal errors can include parallax errors (incorrectly reading a measurement due to an incorrect line of sight), misinterpretation of data, or inconsistent technique in taking measurements. These errors can be minimized through proper training, attention to detail, and following standardized procedures.

**4) Random error:** Random error, also known as statistical error, is caused by unpredictable and uncontrollable factors that affect measurements in a random manner. It is inherent in any measurement process and can occur due to variations in the environment, inherent variability of the measured quantity, or limitations of the measuring instrument. Random errors can be reduced by taking multiple measurements and calculating the average or by using statistical techniques to analyze the data.

In summary, instrumental error is specifically related to faults or limitations in the measuring instrument itself, while systematic error is caused by external factors or flaws in the experimental setup. Personal error is introduced by the experimenter, and random error is inherent in the measurement process. By understanding these types of errors and taking appropriate measures to minimize them, accurate and reliable measurements can be obtained.

Instrumental errors occur due to wrong construction of the measuring instruments . These errors may occur due to hysteresis or friction.