# Physics Unit G482

- Created by: Isaac Brown
- Created on: 21-12-11 21:29

Unit G482 Electron Waves and Photons Definition Page

Conventional Current flows from Positive to negative, Whereas Electron Current flows from Negative to Positive

Charge (Q) = Current * Time

**Definition of a Coulomb **

For a Current of 1 Amp the charge past a point is 1 coulomb in a time of 1 second

**Kirchoff's First Law**

The sum of currents entering at a certain point is equal to the sum of currents leaving that same point

**An Equation for current**

I=A n e v

Where I= Current A= Cross-sectional Area n= Number density and e= Elemental charge

**Definition of Mean Drift Velocity**

The average distance travelled in unit time towards the positive terminal

**Ohm's Law**

For a metal conductor at constant temperature the Current is directly proportional to the Voltage

**Negative Temperature Co-Efficient Resistor or Thermister**

The resistance decreases with increasing temperature (an automatic air conditioner)

**Resistivity= (Resistance * Cross-Sectional Area) /Length**

**Definition of Voltage/Potential Difference/ Electromotive force**

Energy Transferred per unit charge

(Electromotive is gaining/ potential difference is losing)

**Definition of the Volt**

Volt= Joule per Coulomb

**Definition of Power**

The rate of energy transfer electrically Current*Voltage

Definition of the Kilowatt hour

The Energy Transfer by a 1 kilowatt device in 1 hour

Ammeters are connected in series and have a small resistance ideally 0 to take…

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