When you rub an acetate rod with a cloth where do the electrons transfer?
Onto the cloth.
When you rub a polythene rod with a cloth where do the electrons transfer?
Onto the rod.
What is earthing?
When electrons move from an object to the earth, this discharges the object.
How does lightning occur?
Static electricity builds up in clouds and causes a huge spark.
Why must aircraft be earthed before they are refuelled?
To stop the charged aircraft causing a spark that could potentially ignite the fuel causing a fire.
Whats the name of the metal wire used to earth aircraft?
Where can static electricity be used?
Insecticide sprayers and electrostatic paint sprayers.
What is a direct current?
A current thats electrons only flows in one direction.
What’s an alternating current?
A current thats electrons change direction many times a second.
What produces direct currents?
What produces alternating currents?
What is charge measured in?
What do ammeters measure?
True or false:
Ammeters can be placed in series with other circuit components.
Voltage is the same as _______ ___________.
1 Volt = 1 _______ per _________
1 joule per coulomb
What does voltage measure?
The energy transfer from a component for each unit of charge.
What is meant by resistance?
How hard it is for a current to flow.
How is resistance measured?
True or false:
If voltage is applied to any side of a circuit containing a diode is will allow a current to flow.
False, diodes only conduct electricity in one direction.
LDRs have a _____ resistance in the dark and a _____ resistance with light.
Thermistors have a _________ resistance when cold and a _________ resistance when hot.