01 Working As A Physicist Flashcards
Define acceleration
The rate of change of velocity
How to get uncertainty
Range / 2
What is the difference between a base unit and a derived unit?
A base unit is one of seven fundamental units. A derived unit is derived by the multiplication or division of units.
A unit is a measure of quantity, such as distance, mass and time.
What is the order of the scale units?
Femto [10^-15] ->Pico [10^-12] -› Nano[10^-9] -> Micro [10^-6] -> Milli [10^-3] -> Centi [10^-2] -> Deci [10^-1] -> Kilo [10^3] - Mega [10^6] -> Giga [10^9] -> Tera [10^12]
What is the difference between independent and dependent variables?
- Independent variables are what you change in an investigation. Dependent variables are what is observed or measured.
• Independent variables are normally the cause of the effect on the dependent variables.
What is the difference between precision and accuracy?
Precision is determined by the consistency of results; a measurement is precise if the values ‘cluster’ closely together. It is influenced by random errors.
Accuracy is determined by how close the measurement is to the true value; a measurement is accurate if it is close to the true value. It is influenced by random and systematic errors.
What is the difference between error and uncertainty?
- Error is the difference between the measurement and the true value.
- Uncertainty is the interval within which the true value can be considered to lie with a given level of probability. It is determined by apparatus and variables.
How do you work out percentage uncertainty?
Percentage uncertainty =absolute uncertainty / actual or average reading ×100
What is the difference between repeatable and reproducible?
Measurements are repeatable when similar results are obtained from by students from the same group using the same method.
Measurements are reproducible when similar results are obtained by students from different groups using different methods or apparatus.
How can the validity of results be improved?
• Control more variables
• Use more precise measuring equipment
• Obtain more results to reduce uncertainty
What is the difference between random and systematic error?
- Random errors are caused by unpredictable changes in the investigation, often caused by the environment or irregular changes. This usually affects the precision.
- Systematic errors are continuous errors throughout the investigation, and are usually caused by limitations in equipment e.g. zero error. This usually affects the accuracy.
What are all the base units, their symbols, their unit and their base unit
Time - t - s - second
Length - L - m - metre
Mass - m - kg - kilogram
Temperature - T - k - kelvin
Current - I - A -amperes
Amount of substance - n - (no unit) - mole
SA off a sphere equation
4πr²
Sphere volume equation
4/3πr^3
Define velocity
The rate of change of displacement : measured in ms^-1
