8 - Charge and Current Flashcards
Define current
The rate of flow of electric charge
Current equation
I(current) =Q(charge) / t(time)
What is charge?
A physical property that all bodies possess and is either positive or negative. Through electrostatic forces, these charges can interact.
How do charges interact?
Like charges repel and unlike charges attract.
What is the SI unit for charge?
C or Coulomb
What is one coulomb of charge defined as?
The amount of charge that passes a point per second when the current is 1A.
What is the fundamental charge?
1.6x10^-19 - All charges are multiple of the fundamental charge (Charge is quantised) and 1e (electron) has a charge of -1.6x10^-19
What is net charge?
The net charge of an object is expressed as a multiple of e: Q=±ne and depends on the loss or gain of electrons.
How is current produced in a wire?
Metals don’t have a full outer shell of electrons so when they bond, they deposit the free electrons into a sea of delocalised electrons, resulting in positive ions. The negatively charged electrons will be attracted to the positive terminal and repel the negative terminal. The electron move freely from the negative terminal to the positive terminal, resulting in a flow of electrons, resulting in a current.
What is the difference between electron flow and conventional current?
Electron flow is the direction of electron flow from the negative terminal to the positive terminal due to electrons being negatively charged. The opposite is conventional current. Conventional current moves from the positive terminal to the negative as it assumes positive charged carriers (protons) cause current flow. Conventional current was before the discovery of the electron.
What is an electrolyte?
A solution that has ions within it, which can carry charge through the liquid.
What causes current to be produced in the wire during electrolysis?
The flow of electrons. The electrons move to the positive terminal from the negative (opposite of conventional current). The cathode is the side the electrons move towards and the opposite is the anode.
How do ions in the solution move towards the cathode?
The cathode is negatively charged so positively charged ions in the solution (cations) will move towards the cathode.
How do ions in the solution move towards the anode?
The anode is positively charged so negatively charged ions in the solution (anions) will move towards the anode.
How is current in an electrolyte created?
The movement of ions towards the cathode and anode is a flow of charge and so creates an electric current within the solution.