Electricity
- Created by: Ritzy Nanda
- Created on: 04-11-15 00:02
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Current
Current- rate of flow of charge. Charged particles are known as charge carriers I=Q/T
Key Tips: Whilst working out the number of electrons in an equation you have to divide the charge by 1.6 x 10^(-19)
Charge Carriers in different materials
- In insulators there are no delocalised electrons therefore when a potential difference is applied to the matreail there will be no flow of chage because the electrons are not free to move
- In metalic conductors electrons are delocalsied and surround the proton in a sea of elcectrons so when a pd is apllied it pushes the the already free elctrons to move towards positive end
- In semi conductors only some of the electrons are delocalised. They have a negative temperature coefficiant this is because as the temperature increase the value for current also inceases as more electrons cane become free
Potential difference and power
Potenial difference- is defined as work done per unit charge V=W/Q
EMF- the electrical energey produced per unit charge
Work done (J) = Current x Voltage x Change in Time
Power (W) = Current x Voltage
Resistance
Resistance- is defined as R = V/I
You can measure the affects of a change in resistance by making a simple circuit with a variable and fixed resistor also with a voltmeter and ammeter
- Variable resistor is there to make sure that there will be diferrent…
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