Card Set Information
Equation for charge?
It is the flow of electrons
Equation for current?
It is the rate of flow of charge
Equation for voltage/potential difference?
It is the work done per unit charge 1J/c
Equation for energy?
measured in joules
Equation for power?
It is the change in energy over the change it time
Equation for resistance?
units = ohms
It is the impotence to the flow of charge
Equation for coils?
Equation for force?
Equation for weight?
Equation for GPE?
Equation for kinetic energy?
Equation for work done?
Values for quantity
Current flows from big stick of cell to little stick.
A diode monitors the direction of flow.
Transformers are used to step up or down voltage.
What types of radiation are there?
alpha, beta, gamma
How far does radiation travel?
alpha= up to 10cm, highly ionising, blocked by paper
beta= up to 1m, mid ionising, blocked by aluminium
gamma=infinity, least ionizing, blocked by thick lead
What are the masses of different radiation?
alpha= mass of 4, 2 protons and 2 neutrons
beta= mass of 0, charge of -1
gamma= nothing, nucleus just changes from high energy to low energy
What is half life?
The average time taken for half the isotopes/number of nuclei to decay
Equation for density?
Eff=useful energy out/total energy in
What is amplitude, wavelength and frequency?
Wave speed equation?
wave speed(ms-1)=wavelength(m) x frequency(Hz)
Series and parallel circuits
Rules for cells in circuits.
When cells connected in series, total voltage = sum of individual voltages.
When cells connected in parallel, total voltage = voltage of just one cell.
Rules for resistors in circuits.
When resistors in series, resistance is added up.
When resistance in parallel, the total resistance is less than of an individual resistor.
Resistors always have same resistance, unless temperature is changed.
Calculating resistance in parallel.
- 3+ resistors
Rt = total resistance
- 2 resistors
(two R multiplied/two R added)
- any number of identical resistors
resistance of a single one ÷ total num of resistors.
Current in circuits.
In a parallel circuit, current splits.
In a series circuit, current is constant.
Voltage in circuits.
In series, total voltage supplied is divided between components.
Ratio of voltage = ratio of resistance
In parallel,voltage supplied is the same in each component.
Charge prefers the path with least resistance.
Current will prefer to flow through a wire rather than a bulb if given the option.
Equations for speed and acceleration.
acceleration=change in velocity/time
distance-time graph grad=speed
velocity-time graph grad=acceleration
area under v-t graph = distance
Equation for pressure?
force (N)/area (m²)
p=momentum (kg m/s)
v= velocity (ms)
Changes in momentum
F(N)=change in momentum (kgm/s)/time(s)
A low level of radiation thats always there.
Make sure to take this into account
When light is refracted, its wavelength changes, but frequency stays the same.
Refraction is the bending of a wave when it enters a medium with different speed.
When light travels into denser material=bends towards the normal
When light travels into less dense material=bends away from the normal
Light of a lower wavelength gets refracted more than light of a higher wavelength.