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Physics - Batteries

In a battery, chemical potential energy is converted to electrical potential energy. In a battery there are two electrodes made of different substances embedded in an electrolyte. The electrolyte interacts with the electrodes creating a net negative charge on one, the anode and the net positive charge on the other, the cathode. Charges are separated and a potential difference is created between the two external projections of the electrodes called the terminals. 

The electromotive force created by the battery creates a charge flow called a current. The size of this current is measured in charge per unit time or Q/t or coulombs per second. The name given to this unit is amperes (A). So, one ampere equals one coulomb per second. 

Rule number 34: 
Current equals charge divided by time or I = Q/t. For a current to exist, a source of EMF and a conductor is required. There must also be a circuit which is a path between the points of unequal electric potential at the EMF source along which the charge can flow. 

Current is the flow of positive charge. So, when electrons are flowing in one direction, the current is in the opposite direction. In an electric circuit, current flows from the positive terminal on a battery, the cathode, to the negative terminal, the anode.