Physics- Electricity

Physics- Electricity

1. Resistance

   • Whatever opposes the flow of charge. Measured in ohms
   • Resistance+ Current around circuit -
   • Length of wire- longer wire means more resistance
   • thickness- thicker wire means more resistance
   • Material

2. Potential Difference

   • Sometimes called voltage, as it is measured in Volts (V) ,with a voltmeter
   • The p.d across a cell is called the electromotive force (emf). It tells us how strong a cell is.
   • P.d Problems
     • Sum of p.d across a cell in series must equal sum of p.d across other components in the loop
       • V1=V2+V3
     • Sum of p.d in branch of parallel circuit equals sum of p.d across any other parallel branch
       • V1=V2=V3