Electricity

What is the equation for current ?

Current = charge / time

What is the definition of current ?

The rate of flow of charge

What is the definition of an amp ?

There is a current of 1A flowing when 1C of charge passes at a point in 1second

What is conventional flow ?

The flow of electrons from the positive to the negative terminal in a circuit ?

What is an electron current ?

The actual flow of electrons from the negative to the positive terminal in a circuit

Define potential difference ?

The potential difference is the energy transferred per unit charge

What is the equation for potential difference ?

p.d = energy transfers / time

What is the definition of 1V ?

1V is when 1J of energy is transferred when 1C of charge passes

How does p.d (voltage) act in a series circuit ?

The p.d can change though out the circuit when it interacts with components

How does current act in a series circuit ?

It is constant (the same everywhere in the circuit)

How must a voltmeter be connected in order to measure p.d ?

In parallel

How must an ammeter be connected in order to measure a current ?

In series

Why does the ammeter not effect the current in the circuit ?

It is designed to have low resistance

Why does the energy in a circuit decrease over time ?

The cell becomes worn out over time

Why is the potential difference across the battery or cell always the total p.d that is supplied ?

The voltage supplied returns to the cell as 0V , therefore the potential difference either side of the cell is the total pd supplied - 0 = total pd supplied

How does pd interact with resistors ?

pd is split between all the resistors in a circuit in proportion to each other

What is the equation for power ?

Power = energy transferred / time

What is an alternative units for energy and how many joules is it equal to?

kWh (kilowatt hour)

1kWh =3,600 kJ

Define an Electon volt ? (eV)

This is the energy transferred when an electron is accelerated across a pd of 1V

What is the electormotive force ?

electrical energy the battery produces and transfers to each unit of charge

What is the potential ?

The voltage at 1 point

Why does the emf supply less energy than it promises ?

It has resistance , therefore it uses some of that energy to overcome it

How does current act in a parallel circuit ?

1. The total amount of charge/current into is = the total amount of charge/current out of a junction

2. The current is split equally among all the branches in a parallel circuits

(NB : charge and current do the same thing over time at the junction)

How does pd act in a parallel circuit ?

Pd in each branch = pd across the cell

What is the relationship between the number of components in a cell , resistance and current ?

The greater the number of components in a cell , the greater resistance and therefore the lower the current