Additional Physics Topic 2

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  • Created by: Hannah
  • Created on: 23-01-13 11:36

A cell transfers electrical energy to the charge- this is voltage. An ammeter measures the current flowing through a circuit. It must be placed in a series. A component transfer electrical energy into other forms. This causes the electrical energy to drop creating a potential difference. A voltmeter measures the voltage of a cell or potential difference of a component, but it must be placed in parallel to the circuit. 


1. Energy is supplied to the charge at the power sources and this increase the voltage So the more the cell supplies, the more electrical energy their is and the more voltage. 

2. The charge then transfers energy to the components as the charge goes pass which means that energy is being lost in the circuit. The higher the voltage the more the energy that is transferred for a given amount of charge passing through the circuit so 1 volt= 1 joule/coulomb. 

Voltage is the energy transferred per charge and can be calculated by this equation: 

Voltage= energy transferred/charge

or V=W/Q

V (voltage) is in volts (or Joules per Coulomb JC-1)

W (energy transferred but can be written as E for energy) is in joules. 

Q (charge) is in Columbus. 

In a series circuit, the current is the same at any point. 

Current= charge/time

A parallel circuit is one where the current has a choice of routes. The current then splits up equally in the sense that the components are identical. The component and ammeter and the variable resistor are all in series so they can be put in any order around the circuit, but the voltmeter has to be placed parallel to the component being tested. 

The German Physicist Gustav Kirchoff established two laws which helps us understand the function of electric current. 

First Law of Kirchoff

The sum of a current leaving any junction is always equal to the sum of the…


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