Topic 1 - Physics and physical measurement Flashcards
What is the range of magnitude of distances?
10–15 m to 1025 m
(sub-nuclear particles to extent of the visible universe
What is the range of magnitude of masses?
10–30 kg to 1050 kg
(mass of electron to mass of the universe)
What is the range of magnitude of times?
10–23 s to 1018 s
(passage of light across a nucleus to the age of the universe)
What are the fundamental units in the SI system?
- Mass - kilogram
- Length - metre
- Time - second
- Electric current - ampere
- Amount of substance - mole
- Temperature - kelvin
What is the difference between fundamental and derived units?
Fundamental are the base units that are used to derive all the rest of the units
What is the appropriate scientific notation in SI format?
ms–2 instead of m/s2 etc
What is random error?
- Unavoidable error
- Due to limitations of scale, reading issues, human error, difficulties in observation
What is systematic error?
- Something consistently wrong
- Is always bigger or smaller by the same amount
- May be due to zero error or wrongly calibrated equipment
What is the difference between precision and accuracy?
An accurate experiment is one that has small systematic error = evenly distributed around the correct value
A precise experiment has a small random error = similar values close to each other
How can the effect of random errors be reduced?
- Repetition
- Calculating mean value
- Excluding anomalies
Can systematic errors be reduced by repeating readings?
No.
What are the three types of uncertainties?
How are uncertainties represented in graphs?
By error bars
How is the uncertainty of a multiplication or division equation determined?
The fractional uncertainties are added up:
How is the uncertainty of a power relationship determined?
How are vectors added up?
By using a parallelogram:
a + b
What is meant by resolving vectors?
Splitting a vector into two or more of its components
