33-66 Flashcards
(39 cards)
what is an electrostatic force?
it is the force between 2 charges
when a cloth is rubbed on a polythene pole what happens?
the electrons in the cloth move to the pole and the pole becomes negatively charged while the cloth becomes positively charged
to remove the charge off the plane when refueling what do they use?
earth wire to earthen the charged aircraft
formula for charge?
charge = current x time
what is current?
the rate of flow of the charge
current formula
charge/time
voltage formula
work done/charge
work done formula
power x time
unit of a volt
jc^-1
what is ohm’s law?
v= ir
what is resistance?
the oponent that goes against the current flow
electric energy formula
power x time
unit of electric energy
kWh
what is the temperature sensitive resistor?
thermistor
what does a diode do?
it allows current to flow in only one direction
which rule is used to determine the magnetic filed direction?
right hand grip rule
what does the thumb indicate?
the current
how can the strength of the magnetic field be strengthened around a solenoid?
- by adding more turns to the solenoid
- increasing the current flowing through the coil
how does a loud speaker work?
- the alternating current that flows through the coil creates a magnetic field around the wire which pushes a force in the opposite direction and the coil vibrates to produce sound waves
how does a generator work?
a conductor in the coil which is rotating cuts through the magnetic field lines, this magnetic flux induces a voltage so electrical energy turns into mechanical
how does a step up transformer work?
when the number of turns in the secondary coil is more than the primary coil turns the secondary voltage is greater and the output voltage is higher
how does a step down transformer work?
the opposite of a step up
how do you know if a transformer is efficient?
power input = power output
formula for efficienty transformer
Vp Ip = Vs Is
