Foundation Of Physics Flashcards
What is a quantity?
Property of an object
Example of quantities?
Length
Mass
Time
What are the six SI units?
Kilogram
Metres
Second
Ampere
Kelvin
Mole
What is an independent variable?
The variable you change.
What is a dependent variable?
The variable that you measure which is dependent on the other variables.
What should be plotted on the x axis?
The independent variable
What should be plotted on the y axis?
The depenedent variable
What is uncertainty?
An estimate of the difference between a measurement reading and the true value.
What are two types of measurements errors that lead to uncertainty?
Random errors
Systematic errors
What is a random error?
Unpredictable fluctuations in an instruments readings due to uncontrollable factors
What do random errors affects?
The precision of the measurements taken,causing a wider spread of results about the mean value.
How do random errors occur?
From the person carrying out the measuring or reading the instrument incorrectly.
What are examples of random errors?
Reaction time of a person
Parallax errors
What is a parallax errors?
A reading appearing different due the position someone is looking at it,
How do you reduce random errors?
Repeat the measurements several times and calculate an average from them.
What is a a systematic error?
Using a faulty instrument or flaws in the experimental method.
How does a systematic error affect readings?
It affects the accuracy.
This error is repeated every time the instrument is used or the method is follows so affects the accuracy of the readings.
Examples of systematic errors?
Forgetting to Tate the mass balance
Not reading the meniscus at eye level.
How do you reduce systematic errors?
Instrument can be recalibrated, or different one is used.
How do systematic errors affect a graph?
The graph is away from the origin
What is a zero errors?
A type of systematic error where the instrument gives a reading when the real reading is zero.
Example of zero erors?
A top-ban balance starting of a 2g rather than 0g.
How do you remove zero error?
Removed the difference of the offset value from each value.
Define precision
The closeness of agreement between independent measurements obtained under the same conditions. It depends only on the distribution of random errors and does not relate to the true value
When repeating a measurement when can the readings be said to be precise?
When the values are very similar to each other or the same.
What is accuracy?
A measurement is considered accurate if it is close to the true value.
How can accuracy be increased?
Repeating the measurements and finding the mean of the results.
What does repeating measurements do?
It removes an anomalies from the final results
What is the difference between precision and accuracy?
Precision- the ability to take multiple readings with an instrument that are close to each other.
Accuracy is the closeness of those measurements to the true value of.
What is accuracy?
A ,measurement of the closeness of agreement between an individual test result and the true value. If a tests result is accurate, it is close agreement t with the true value.
What affects accuracy?
Systematic errors
How could you increase accuracy?
Example
Using a micrometer rather than a ruler as it has a higher resolution
What affects precision
Random errors
What is an independent variable?
The only variable that should be changed through an experiment
What is a controlled variable?
Any other variable that may affect the results of the experiment need to be controlled or monitored
What is a dependent variable?
The variable that is measured to determine one the outcome of an experiment
What is resolution?
The smallest change in quantity being measure of a measuring instrument that gives a perceptible change in the reading.
Can random errors be removed completely?
No they can only be reduced by taking repeat and finding the average of the readings
Can random errors be removed completely?
No they can only be reduced by taking repeat and finding the average of the readings
What type of errors do analogue instrument have?
Zero errors
Parallax errirs
What type of errors do analogue instrument have?
Zero errors
Parallax errirs
What type of errors do digital instruments have?
Zero error
How can parallax errors be reduced?
Reading the value on a scale only when the line of sight is perpendicular to the scale of readings
What is an uncertainty in a measurement?
An intervals that indicates a range within which we are reasonably sure that the true value lies in.
What does uncertainty depend on?
Systematic errors and random errors
When using an apparatus that has analogue scale what is the uncertainty?
It’s half the resolution
What is the uncertainty for a ruler?
When measuring a distance the uncertainty has to be take account for twice and is overall 1mm
For digital apparatus what is the uncertainty?
It is equal to the resolution of the apparatus.
