the data sheet aqa as level. data - fundamental constants and values quality – highlight the ones...
TRANSCRIPT
DATA - FUNDAMENTAL CONSTANTS AND VALUES
• Quality – highlight the ones you have come across – most are from A2!
• Symbol • Value - note most are 3 sig figs!• Units – a useful place to look if you
forget the case of the letter - N, kg, J, W, C, m etc.
Quarks• They even tell
you that antiquarks have opposite signs....
• The fact that baryon number is in thirds tells you a baryon has three quarks in it!
Photons – Electromagnetic quanta of energy and/or waves
• The first two deal with e.m. Waves
• deBroglie links particles (momentum – mass) and waves (wavelength) – used to find the wavelength of a mass particle
Current - I
• Electric current is how much charge moves in unit time (rate of flow of charge)
• Need to know Q is Quantity of charge
Potential difference - V
• Potential difference is the energy transferred per unit charge (coulomb).
Resistance - R
• The electical resistance of a component is the ratio of the potential difference across the component to the current passing through it.
Electromotive force - e• The electromotive
force is the energy per coulomb produced by a source of electricity.
EMF - e
• EMF = voltage across external circuit (IR) plus voltage across the internal resistance (called ‘lost volts’)
• Now V = IR – so we can replace that...• e = V + Ir
Resistivity is not another word for resistance!
• Resistivity is resistance of a specimen of unit length and unit cross sectional area.
• Unit is Wm not W – they are different!
AC
• Io is the peak current
• Vo is the peak voltage
• IRMS is the root mean square current
• VRMS is the root mean square voltage
Oscilloscope
• This is in the waves section – and is needed to interpret the trace on an oscilloscope.