Topic 7 Flashcards
Why is there a short circuit
an alternate path of zero resistance is present
Define electric current
Rate of flow of electric charge
What is the purpose of a reflective strip on an ammeter
to prevent parallax error by observing that pointer and image are aligned
Define electromotive force
work done by source in driving a unit charge(C) around a complete circuit
Define potential difference
work done in driving a unit charge(C) across two points in a circuit
Define resistance
Measurement of difficulty of electric current to pass through conductor
Define electrical resistance
Ratio of potential difference across circuit component to current flowing through it
define power
rate of work done or rate of energy transfer
what colour is the live wire
brown
what colour is the earth wire
yellow and green
what colour is the neutral wire
blue
What is the function of the earth wire
If the live wire were to touch the casing, the earth wire provides a conducting path for current to flow to the ground instead of the person, since the earth wire is a low resistance wire. The large current blows the fuse, breaking the circuit.
