Chapter 2 - Electricity: Energy, Power and Resistance Flashcards
Define Diode
A component that allows current through in one direction only. In the correct direction, diodes have a threshold voltage (typically 0.6 V) above which
current can flow
Define Electromotive Force
The energy supplied by a source per unit charge passing through the source, measured in volts
Define Filament Lamp
A bulb consisting of a metal filament, that heats up and glows to produce light. As the filament increases in temperature, its resistance increases since the metal ions vibrate more and make it harder for the charge carriers to pass through
Define Light-Dependent Resistor
A light sensitive semiconductor whose resistance
increases when light intensity decreases
Define Ohmic Conductor
A conductor for which the current flow is directly proportional to the potential difference across it, when under constant physical conditions
Define Ohm’s Law
The current and potential difference through an ohmic conductor held under constant physical conditions are directly proportional, with the constant of proportionality being resistance
Define Potential Difference
The difference in electrical potential between two points in a circuit. It is also the work done per coulomb to move a charge from the lower potential point to the higher potential point. It is measured in Volts
Define Power
The rate of energy transfer in a circuit. It can be calculated as the product of the current and the potential difference between two points. It is measured in Watts
Define Resistance
A measure of how difficult it is for current to flow through a material
Resistivity
A measure of how difficult it is for charge to travel through a material. It is proportional to the object’s resistance and cross-sectional area, and inversely proportional to the object’s length. It is measured in Ohm metres.
