Ch4 Electric circuits Flashcards
charge
Q=It
potential difference
V=IR
Ohm’s law
the current through a resistor at constant temperature is directly proportional to the potential difference across the resistor
resistance
R=V/I
diode characteristics
current only flows in one direction
high resistance in reverse direction
filament lamp characteristics
The resistance of a filament lamp increases as the temperature of the filament increases
thermistor
resistance decreases as the temperature increases
Series circuit rules
Same current through each component
total pd of power supply is shared between components
Parallel circuit rules
the potential difference across each component is the same
the total current through the whole circuit is the sum of the currents through the separate branches
Rtot = R1xR2/R1+R2
Force between charged objects
like charges repel
unlike charges attract
production of static electricity
certain insulating materials are rubbed against one another
Negatively charged electrons are rubbed off one material and on to the other
material that gains becomes negatively charged
material that loses is left with an equal positive charge
charge of…
- proton
- neutron
- electron
- positive
- neutral
- negative
mass of…
- proton
- neutron
- electron
- 1
- 1
- 1/2000
sparking
if force between two oppositely charged objects is too strong
electrons are pulled out of air molecules by the force of the field
electrons hit other air molecules and knock electrons out of them
creates a sudden flow of electrons between the two objects
electric field
created around a charged object
the second charged object experiences a force because of the field
