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31 Cards in this Set
- Front
- Back
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What is the Accepted Value? |
The value of the Most Accurate measurement available. |
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What is Accuracy? |
A measure of confidence in an accurate measurement. |
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How is accuracy often expressed? |
An upper and lower limit based on uncertainty. |
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What is an Accurate measurement? |
A measurement taken with accurately calibrated instruments with no systematic errors. |
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What is the dependent variable? |
The value that changes as a result of the independent value being changed. |
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What is error? |
The difference between a measurement and its accepted value. |
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What is the independent variable? |
The variable that's value is controlled or changed by experimenter. |
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What is linearity? |
A linear instrument has evenly spaced graduations on its scale with each spacing of equal value. |
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What is the mean value? |
The sum of all the readings divided by the number of readings. |
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What is the percentage uncertainty? |
The uncertainty / mean x 100. |
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What is precision? |
The degree of exactness to which a quantity or value can be obtained. |
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What is the precision of a constant reading? |
The precision of the instrument used. |
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What is the precision of a range of readings? |
Half the range of the readings. |
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What is the precision of an instrument? |
The smallest non zero reading that can be measured. |
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What is the range? |
The difference between the smallest and largest values. |
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What is random error? |
Errors with no pattern or bias. |
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How is the effect of random error reduced? |
Taking more repeat readings and finding a mean value. |
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What is reliability? |
The extent to which results remain consistent over repeated measurements. |
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What is sensitivity? |
Scale reading / quantity measured. |
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What is systematic error? |
Errors which show a pattern or bias. |
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What is a common cause of systematic error? |
Instruments being incorrectly calibrated (zero error). |
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What is uncertainty? |
An expression for the set of value which are likely to include the accepted value. |
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What is a valid measurement. |
A measurement which gives the required information via an acceptable method. |
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What is zero error? |
A systematic error caused when an instrument gives a non zero reading for a true value of zero. |
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How can the effect of zero error be reduced? |
Adding/subtracting the zero error from all the results. |
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What is parallax error? |
Error caused by misreading an instrument due to looking at a needle from an incorrect angle. |
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What is a hypothesis? |
An untested idea or theory based on observations. |
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How do you calculate uncertainty for addition? |
Add the absolute uncertainties |
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How do you calculate uncertainty for multiplication? |
Add the relative uncertainties. I.e the error or percentage error. |
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How do you calculate uncertainty for powers? |
Multiply the relative uncertainty by the power. |
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What is resistivity? |
Resistivity = resistance times area over length. |
