Topic 6 - Electricity Flashcards
Charge carriers
Charged particles that move through a substance when a pd is applied across it.
Circuit rule for current (Kirchhoff’s first law)
- The current passing through two or more components in series is the same through each component.
- At a junction, the total current in = the total current out.
Circuit rules for pd (Kirchhoff’s second law)
- For two or more components in series, the total pd across all the components is equal to the sum of the pds across each component.
- The sum of the emfs round a complete loop in a circuit = the sum of the pds round the loop.
Critical temperature of a superconducting material.
Temperature at and below which it’s resistivity is zero.
Electrolyte
A solution or molten compound that conducts electricity.
Electromotive Force (EMF)
The amount of electrical energy per unit charge produced inside a source of electrical energy.
Internal resistance
Resistance inside a source of electrical energy; the loss of pd per unit charge in the source when current passes through it.
Light-dependent resistor
Resistor which is designed to have a resistance that changes with light intensity.
Negative temperature coefficient
The resistance of a semiconductor decreases when its temperature is increased.
Ohm’s law
The pd across a metallic conductor is proportional to the current, provided the physical conditions do not change.
Positive temperature coefficient
The resistance of metal increases when its temperature is increased.
Potential difference
Work done or energy transferred per unit charge between two points when charge is moved from one point to the other.
Potential divider
Two or more resistors in series connected to a source of pd.
Resistance
Pd/current
Resistivity
Resistance per unit length x area of cross-section
