Electricity - Section 6 AQA
- Created by: Alicia_H
- Created on: 16-10-16 08:17
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- Electricity
- Current
- I=Q/t
- I=Current (A,Amps)
- Measured using ammeter in series
- Ammeter = zero resistance
- Measured using ammeter in series
- Q=Charge (C,Coulomb)
- The rate of flow of electrons
- t=Time (s,seconds)
- I=Current (A,Amps)
- I=Q/t
- Potential Difference
- V=W/Q
- V=Voltage (V,Volts)
- 1V=1J/C
- Measured using Voltmeter in parallel
- Voltmeter = infinitely resistant
- Q=Charge (C,Coulomb)
- W=Work done (J,Joules)
- V=Voltage (V,Volts)
- V=W/Q
- Resistance
- R=V/I
- I=Current (A,Amps)
- R=Resistance (?, ohms)
- Ohmic Conductors
- Ohms Law: Provided physical conditions remain constant the current through an ohmic conductor is directly proportional to the current through it
- I is directly proportional to V
- Graph is a straight line through the origin
- Resistors
- Variable Resistor
- Resistance can be varied
- Thermistor
- Resistance decreases as temperature increases
- Variable Resistor
- Ohmic Conductors
- V=Voltage (V,Volts)
- Resistivity
- resistivity =(RA)/l
- l=Length (m,metres)
- R=Resistance (?, Ohms)
- Resistivity (?m, ohm-meters)
- A=cross-sectional area (m2)
- Super-conductors
- Zero Resistivity
- Uses: Power Cables Electromagnet Fast Circuits
- resistivity =(RA)/l
- R=V/I
- Power
- P=VI
- P=I²R
- Electrical Energy
- E=VIt
- E.m.f and Internal Resistance
- emf=E/Q
- emf=I(R+r)
- emf=E/Q
- Current
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