Topic 5 & 11 Flashcards
Current
Rate of flow of charge
Ideal ammeter
An ammeter with zero resistance
Ideal Voltmeter
A voltmeter with infinite resistance
Kirchhoff’s 1st Law
The sum of currents flowing into a junction is equal to the sum of currents flowing out of that same junction
Kirchhoff’s 2nd Law
The sum of the emfs in any closed loop is equivalent to the sum of the potential differences in that loop
Reisistance
Resistance is directly proportional to the potential difference, and inversely proportional to the current
Ohm’s Law
The current is proportional to the potential difference providing the temperature is constant (resistance is constant)
Electromotive Force
Total energy per unit charge made available by the chemical reaction in the battery
Electric field strength
Electric force per positive unit test charge (E=F/q)
Magnetic Flux
Magnetic flux = BAcos0
Magnetic flux linkage
(Magnetic flux) x (number of coils)
Faraday’s Law
The emf induced by a time changing magnetic field is proportional to the rate of change of the flux linkage
Lenz’s Law
The direction of induced emf is such that it produces a magnetic field whose direction opposes the change in magnetic field that produced it
Capacitance
Ratio of charge stored in a device to the potential difference across the device
Time constant
The time required to discharge the capacitor through a resistor to 36.8% of its initial charge voltage
