Sources and Types of Error

What is the definition of error in measurements?

• The difference between random and systematic errors.

• The difference between the measured value and the true value.

• The variation in measured values due to external factors.

• The average of multiple measurements.

Answer explanation

Error in measurements is defined as the difference between the measured value and the true (actual) value.

Which of the following is an example of random error?

• Faulty instrument calibration

• Electrical noise in a circuit

• Measurement bias due to human error

• Poorly maintained instruments

Answer explanation

Electrical noise in a circuit is an example of random error

Errors that remain constant or change in a regular manner with each measurement are known as:

• Random errors

• Systematic errors

• Parallax errors

• Zero errors

Answer explanation

Errors that remain constant or change in a regular manner, even with repeated measurements, are called systematic errors.

Parallax error occurs when:

• Instruments are not calibrated properly.

• Electrical noise affects measurements.

• Random variations are present in measurements.

• The user reads an instrument at a different angle or line of sight.

Answer explanation

Parallax error occurs when the user reads an instrument at a different angle or line of sight, leading to an incorrect measurement.

How can systematic errors be minimized?

• By using a more precise instrument

• By repeating measurements multiple times

• By calibrating instruments properly and maintaining them

• By ensuring that random errors are eliminated

Answer explanation

Systematic errors can be minimized by calibrating instruments properly and maintaining them to ensure accurate readings.

Random errors can be assessed:

• empirically

• statistically

• experimentally

• by performing sensitivity analysis

Answer explanation

Random errors can be evaluated through statistical analysis and can be reduced by averaging over a large number of observations.

Random errors lead to a lack of:  

• accuracy in the measurement. 

• precision in the measurement.

• significant digits in the measurement.

• gradation of the measuring instrument

Answer explanation

Random error produces different results which will degrade the precision in measurement.

Systematic errors lead to a lack of:  

• accuracy in the measurement. 

• precision in the measurement.

• significant digits in the measurement.

• gradation of the measuring instrument

Answer explanation

Systematic error produces values that are off in a regular fashion which can lead to poor accuracy in measurement

What is zero offset or zero error in a measuring device?

• It refers to the device's tendency to always measure zero, regardless of the actual value.

• It occurs when there is a measured value, even if the true reading should be zero.

• It is a calibration error that only affects electronic balances.

• It is a term used in mathematics to describe a zero point on a measurement scale.

Answer explanation

Zero offset or zero error is a phenomenon where a measuring device provides a non-zero reading when it should ideally read zero. This can introduce inaccuracies in measurements. It is essential to either re-zero the instrument or record the zero error and adjust your final measurements accordingly to ensure accurate results in various measuring devices like rulers, micrometer calipers, and electronic balances.

What are random errors in the context of measurements?

• They result from systematic biases in the measuring instrument.

• They occur when repeated measurements consistently produce the same result.

• They are associated with variations in measurements when repeated measurements produce varying results.

• They are errors that can be completely eliminated through careful calibration.

Answer explanation

Random errors, as described in option C, are uncertainties in measurements caused by inherent variations and fluctuations in the measurement process itself. These errors lead to slightly different results when the same measurement is repeated multiple times.