1Electric current
a flow of electric charge.
2*Current in a metal conductor: what is it?
*An electric current in a metal conductor is a flow of electrons.
3Size of an electric current
The amount of charge passing any point of a conductor per second.
4*Current at every point in a circuit
*The current is the same at
every point in a series
circuit.
5*How to use an ammeter?
*Connected in series
6Unit of potential difference
Joule per coulomb (J C⁻¹)
AND
Volt (V)
7*What is the potential Difference between two points in a circuit
*The P.D between two points in
a circuit is the energy lost by
one coulomb as it moves
from one point to the other.
8*How to use a voltmeter
*A voltmeter is always connected in parallel with the part of the circuit
across which the p.d. is to be measured.
9Electromotive Force (emf)
A voltage when applied to a circuit
10Resistance
The ratio of the potential difference to current.
11The Ohm Ω
A conductor has a resistance of 1 ohm if the current through it is 1 A when the p.d. across it is 1 volt.
12Resistivity
ρ = RA ÷ l
ρ= Resistivity
R = Resistance
A = Cross sectional area
l = Length
13Ohm's Law
states that at a constant temperature, the current flowing through a conductor is directly proportional to the potential difference.
14*Uses of a wheatstone bridge
*(know like 2 maybe)
• Temperature Control (Thermostat)
• Flame failure device
• Fire Alarm
•Strain Gauge
15Joule's Law
states that the rate at which heat is produced in a conducor is directly proportional to the square of the current provided its resistance is constant
16ion
A charged atom or group of atoms
17*Charge carriers in an electrolyte
*Positive and negative ions
18Direct Current
Current that flows in one direction only
19Alternating Current
Current that constantly changes direction
20Kilowatt-hour
The amount of energy used by a 1000 W appliance in 1 hour