Type of error

Error- 

During measurements there are a lot of facts involved in measured quantity which may affect the measured value. it may be temperature,Humidity,operators mistakes etc

Hence the Error is defined as the difference between the measured value and its true value.

The true value is pre-defined  value which is obtain for ideal condition or set a specific value by a person or organisation.(e.g.- 1m = 100cm is not god gifted quantity but it is just used as a reference for measurement of length.)

There are some major type of error found during measurement-

1. Goss error
2. Systematic error
3. Random error

It is classified into three categories

• Instrumental error
• Environmental error
• Observational error

Instrumental error-                 

It is further classified into three categories

• Loading effect
• Misuse of instrument
• Inherent shoot coming into measurement

Gross error-

This error basically takes into account human oversight and other mistakes while reading, recording and the readings. The most common of errors, the human error in the measurement fall under this category of errors in measurement.
E.g.- suppose the instrument shows the reading as 32 and by mistake, experimenter read it as 52 than it falls into Gross error
remedy

• Proper care should be taken during the experiment reading and recording the data
• The experimenter should take three or more experiment to minimize this error.
• Some error can be found easily by comparing two or more experimental data.

Systematic Error-

This error causes mainly due to the measurement systems.
Instrumental error-

• These errors arise due to wrong construction and calibration of the measuring instruments.
• Such errors arise due to the hysteresis of the equipment or due to friction.
• The equipment being used is faulty due to misuse or neglect which changes the reading of the equipment.
• The zero error is a very common type of error. This error is common in devices like vernier calipers and screw gauge.
• The zero error can be either positive or negative. Sometimes the readings of the scale are worn off and this can also lead to a bad reading.

Zero Errors- Any indication that a measuring system gives a false reading when the true value of a measured quantity is zero, e.g. the needle on an ammeter failing to return to zero when no current flows. A zero error may result in a systematic uncertainty.
The instrumental error may cause due to 

1. Loading effects-Loading Effect hugely affects Electrical Measuring Instruments. A Measuring Instrument is supposed to measure a particular quantity without drawing any power from the system in which it measures. However, in most of the analog measurements, the Instrument does draw some power without which it cannot measure the quantity.
2. Misuse of instruments- The error occurs in the instrument because of the fault of the operator. A good instrument used in an unintelligent way may give an enormous result.
3. Inherent shoot coming into the measurements- Such types of errors are inbuilt in instruments because of their mechanical structure. They may be due to manufacturing, calibration or operation of the device. These errors may cause the error to read too low or too high.

Environmental error-
This type of error arises due to conditions of the external environment to the instrument like temperature, pressure, and humidity and can also include external magnetic field. If we measure the temperature under the armpits and during the measurement, if the electricity goes out and the room gets hot, it will affect our body temperature thereby affecting the reading.

• Maintain the temperature and humidity of the laboratory constant by making some arrangements.
• Ensure that there should not be any external magnetic or electrostatic field around the instrument.

Observational error-

• As the name suggests these types of errors are due to wrong observations.
• The wrong observations may be due to PARALLAX.
• In order to minimize the PARALLAX error highly accurate meters are required, provided with mirrored scales.