Unit 0: Revision Flashcards
Precision (repeatability)
The degree of exactness in a measurement
Accuracy
The closeness of a measured value to the standard
Random Error
- Errors caused by human factor
- Should be minimized as much as possible
- Can be minimized by repeating trials (to receive the average of a trial)
Systematic Error
- Error/Offset in the instruments used for experiment
- Both random and systematic errors are inevitable in a lab
Analog Measurement Precision
Estimate to one digit beyond smallest marking
Analog Uncertainty Range
± half the smallest division
Digital Measurement Precision
Go the least significant digit’s place
Digital Uncertainty Range
± the smallest division
Significant Digits in the Uncertainty
Typically 1 (sometimes 2)
Precision in Measurement
Must match uncertainty (i.e. same number of decimal places)
Uncertainty in dependent variable across trials (given constant value of independent variable)
ΔY = (Ymax - Ymin)/2
Rules of Data Tables (title and subtitle)
- Title
- Subtitle for independent and dependent variables
Rules of Data Tables (uncertainties)
- Uncertainties (identical or different for each trial)
- No. of decimal places for data equal to that of the uncertainty
Gradient of LOBF
- Measures the value of an independent variable by the dependent variable
- Ex: Time and velocity
Y-intercept of LOBF [definition]
The measured value of the dependent variable when the independent variable is 0
Y-intercept of LOBF [implications]
Can show discrepancies in the starting point and/or the data as a whole
Line of Best Fit (LOBF) rules
- Must meet the points in a graph and/or their uncertainty range
- Doesn’t usually start at a y-value of 0 (depending on the graph)
LOBF degree of equation
Depends on what graph is shown (ex: Exponential, Linear)
Steepest and Shallowest LOBFs
Drawn LOBFs are often accompanied by a drawn steeper and shallower LOBF
LOBF uncertainty
The uncertainty between the gradients and y-intercepts of the steepest and shallowest LOBFs
Uncertainty in gradient (slope) of LOBF
ΔM = (Mmax - Mmin)/2
Uncertainty in y-intercept of LOBF
ΔB = (Bmax - Bmin)/2
“X is proportional to Y”
- The x-y relationship is linear
- (if asked to list two points) The dependent variable starts at 0
Uncertainties from data:
- The x-y relationship is linear
- For certain: the dependent variable starts at 0
Uncertainties from data: y = a ± b
Δy = Δa+ Δb
Uncertainties from data: y = ab/c
Δy/y = Δa/a + Δb/b + Δc/c
Uncertainties from data: y = a^n
Δy/y = n|Δa/a|
Fundamental Unit
- Those independent of other units
- Serve as foundation for all derived units in physics
Examples of Fundamental Units [A]
- Length (m)
- Mass (g)
- Time (s)
Examples of Fundamental Units [B]
- Temperature (K, °C)
- Current (amp)
- Substance quantity (mol)
Derived Unit
Those stated in terms of (or derived from) basic units
Examples of Derived Units [A]
- Frequency (Hz)
- Energy/Work/Heat (J)
- Pressure (Pa)
- Angles (Degree, Radian)
Examples of Derived Units [B]
- Electric Charge (C)
- Electric Resistance (Ω)
- Force (Newton)