Prefixes & Foundations Flashcards
Peta (P)
x10^15
Tera (T)
x10^12
Giga (G)
x10^9
Mega (M)
x10^6
Kilo (k)
x10^3
Deci (d)
x10^-1
Centi (c)
x10^-2
Milli (m)
x10^-3
Micro (ų)
x10^-6
Nano (n)
x10^-9
Pico (p)
x10^-12
Femto (f)
x10^-15
Base units for amount of substance
Mole - mol
Base units for Force
F = ma
N - kg m s ⁻²
Base units for pressure
P= F/A
Pa - kg m⁻¹ s⁻²
Base units for energy/work
E=1/2mv²
J - kg m² s⁻²
Base units for power
Power = Work/time
W - Kg m² s⁻³
Base units for Electric charge
C = amps per second
C - A s
Base units for voltage
V = P/I
V - Kg m² s⁻³ A⁻¹
Base units for electrical resistance
Ω = V/I
Ω - Kg m² s⁻³ A⁻²
Base units for capacitance
C = Q/V
F - Kg⁻¹ m⁻² s⁴ A⁻²
Base units for specific heat capacity
C = Q/m△t
J kg⁻¹ K⁻¹ - m² s⁻² K⁻¹
How do you define quantities?
- The product of… (x)
- The sum of… (+)
- The rate of… (÷t)
- The … per unit … (÷)
- The product of … per unit … (x ÷)
Define power
The rate of doing work
Define density
The mass per unit volume of a substance
Define spring constant
Force applied per unit extension or change in length
Define moment
The product of a force applied and perpendicular distance from the pivot
Define momentum
The product of mass and velocity
Define velocity
The rate of change of displacement
Define acceleration
The rate of change of velocity
Define electric current
The rate of flow of electric charge
Define p.d (voltage)
The work down per unit charge
Define the Pascal
The pressure when a force is perpendicular to an area
Define the joule
The work down when a force of 1N moves an object 1m
Define the coulomb
The charge when a current flows for one second
Define the volt
The p.d when 1J of work is done to move a charge of 1C between two points
What is a random error?
Errors that result in a measurement varying unpredictably. It cannot be corrected for just mitigated by repeat readings.
What is a parallax error?
A type of random error - from observing the making the same measurement from a different position
What is a systematic error?
Errors that result in a measurement differing from the true value by a consistent amount each time
What is a zero error?
Specific type of systematic error - from a instrument that is not calibrated correctly to be able to record zero accurately
What is the true value?
The value that would be obtained in an ideal/perfect experiment
What does resolution mean?
The smallest change in measurement and instrument can make
What does uncertainty mean?
The interval in which the true value could be expected to lie usually either +/- half the resolution or half the range
What is absolute uncertainty?
The actual amount by which measurement/result could vary
What is the percentage uncertainty?
The proportion by which measurement/result could vary
What does accuracy mean?
How close the results/measurement is to the true value
What does precision mean?
How close repeated results/measurements are to each other
4 ways in which uncertainty can be reduced in an experiment
- Take multiple readings and find a mean
- Use an instrument with a better resolution (micrometer)
- Use a larger measurement to reduce percentage uncertainty
- Time multiple oscillations/revelations to reduce percentage uncertainty (oscillating pendulum)
If the measurements of the same quantity are added or subtracted, what happens to the absolute uncertainty?
They are added together
If the quantities are multiplied or divided, what happens to the percentage uncertainty
They are added together to find a total percentage uncertainty
If the same quantity is raised to a power, what happens to the percentage uncertainty?
The percentage uncertainty of the quantity is multiplied by the magnitude of power
How do you calculate percentage uncertainty in a graph?
Difference between the gradients of the error bar and line of best fit
÷
Gradient of the line of best fit
X 100
