Working as a Physicist Flashcards
SI Base Unit of Length?
Metre (m)
SI Base Unit of Mass?
Kilogram (kg)
SI Base Unit of Time?
Second (s)
SI Base Unit of Current?
Ampere (A)
SI Base Unit of Temperature?
Kelvin (K)
SI Base Unit for an amount of a substance?
Mole (mol)
What are the Prefixes?
Tera (T) = 10^12
Giga (G) =10^9
Mega (M) =10^6
Kilo (k) = 10 ^3
milli (m) =10^-3
micro (u) = 10^-6
nano (n) = 10^-9
pico (p) = 10^-12
What are the SI Base Units?
Length, Mass, Time, Current, Temperature and Amount of a substance
How do you convert between prefixes?
Convert upwards on each by dividing by 1000 and downwards on each by multiplying by 1000.
What are the derived units?
Speed, acceleration, force, energy, power, pressure, charge, potential difference and resistance.
Derived Units of Speed / Velocity
ms^-1
Derived Units of Acceleration
ms^-2
Derived Units of Force (Newtons)
kgms^-2
Derived Units of Energy (Joules)
kgm^2s^-2
Derived Units of Power (Watts)
kgm^2s^-3
Derived Units of Pressure (Pascals)
kgm^-1s^-2
Derived Units of Charge (Coulombs)
As
Derived Units of Potential Difference (Volts)
A^-1kg^2s^-3
Accurate Definition
How close the measured value is is to the true value
Derived Units of Resistance (Ohms)
A^-2kg^2s^-3
Precise Definition
Repeats are close together
Random Error Definition
A different error every time
Systematic Error
A error that is the same every time
Resolution
Smallest interval measure
Zero Error
Measurements don’t begin at the true error
Uncertainty Equation
Percentage Uncertainty = (Uncertainty / Measured Value) x 100
What is the uncertainty when quantities are added or subtracted?
The uncertainty is the sum of the absolute uncertainties.
What is the uncertainty when quantities are multiplied or divided?
The total percentage uncertainty is the sum of percentage uncertainties.
What equation is used to draw a straight line graph?
y = mx +c
What axis is the independent variable?
x - axis
What axis is the dependent variable?
y - axis
What happens if the equation has a +c value?
The graph does not begin at zero.
Independent Variable Definition
A variable that isn’t changed by other variables you are trying to measure and you change it throughout the experiment.
Dependent Variable Definition
A change that happens because of the independent variable.
Control Variable Definition
A property that remains constant and unchanged throughout the experiment.
