There are two ways of considering current direction. The first is the truth: that electrons flow from low potential to high potential (a bit like rolling uphill) as they are negatively charged. This is not very intuitive.
Instead we assume that the charged particles in an electrical circuit are positive, flowing from the positive terminal of the battery to the negative terminal. Since current in a loop is the same throughout, this assumption does not affect our calculations.
Key Concepts
If there is a potential difference between the ends of a resistor, charge will flow. The rate of flow of charge is current.
If two charged bodies are connected by a conductor, charge will flow until there is no potential difference between them. If one of those bodies is the Earth, charge will flow until the potential of the body is 0 V.
This is because the Earth is a vast repository of charges, and so it is able to provide or take any charge required in order to make a body neutral.
Use quizzes to practise application of theory.
START QUIZ!
The diagram represents a section of conductor.
The number of electrons in this section is.
The number of electrons per unit volume x volume
The diagram represents a section of conductor.
The time for an electron to travel the length of the section is:
time = displacement/velocity
The motion of electrons is best described as:
Electrons keep hitting lattice atoms so have a jerky motion but drift with constant speed.
View the hidden animation then use the words below to explain what it represents.
velocity, atoms, lattice, electrons, drift
The green circles represent the atomic of a conductor and the blue balls are . In the upper part of the animation there are no so the accelerate through the conductor. In the lower part the gets in the way of the . The lose energy each bounce so instead of accelerating they move with a constant average this is called the .
How much of Current have you understood?
Twitter 
Facebook 
LinkedIn