Static Electricity Flashcards
What is electric current?
The rate of flow of charged particles
What is the distribution of current in a circuit the consequence of?
Of the charge conservation
Why can only insulators be charged?
Because you are only charging the surface
And metals allow charge to flow through them to make it neutral again
What is the charge on one electron?
-1.6 x 10^-19 C
Why is there a maximum charge that you can accumulate?
You’re limited time the material you have got and it’s surface
What is electrostatic charge defined as?
The absence or excess of electrons
What is an important law about charge?
Charge is always conserved
Describe charge by contact
When 2 objects touch the electrostatic electrons transfer from one object to another until equilibrium is reached
This results in both objects having the same type of charge
Describe temporary charge
When a charged object is adjacent (but NOT TOUCHING) to an uncharged object, the charges in the uncharged object redistribute
There is no change in the net charge of the uncharged object
Describe charge by induction (polarization)
An object charged by induction has the opposite charge as the charging object
Initially the charge on the uncharged object polarizes and then a ground is provided to remove some of the charge
The 2 objects never touch each other
How are positive and negative charges on objects created?
POSITIVE - object loses electrons
NEGATIVE - object gains electrons
Describe POLARIZATION
An unequal distribution of electrons in an object
E.g. electrons in an object repelling a negative polythene rod so one half of the object is negative and the other is positive
Can polarization occur in insulators too?
NO because they don’t conduct charge and so the electrons can’t flow to one end
Why does the gold leaf move when a negatively charged rod is brought close to the gold leaf electroscope?
Because the electrons in the GLE repelled against the negative charge on the rod
This makes the electrons move down to the leaf & rod
Like charge repel so the leaf repels against the rod and moves
How can you charge the GLE by induction?
Charge the rod & bring it near to the GLE but DONT TOUCH IT
This polarizes it
Then place your finger on the metal plate to earth it and allow electrons to flow through
Then remove your finger and the leaf would move = as like charges repel
