Pages 0-95 Flashcards
What is unit is the charge measured in?
Coulomb
What is unit is energy measured in?
Joule
What is unit is the resistance measured in?
Ohm
What is unit is the potential difference measured in?
Volt
What is unit is power measured in?
Watt
What is unit is the electrical current measured in?
Ampere
Voltage x current = ?
Power
Power / energy = ?
Time
What is the main disadvantage to resistance in a cable?
Heat (loss of energy).
What is a benefit of increasing cable cross size?
Power loss can be minimised.
In terms of + and - which way does current flow?
Current flows from positive to negative and electron flows from negative to positive.
What does EMF stand for?
Electromotive force.
What is potential difference?
The change in energy levels measured across the load terminals.
Current x resistance = ?
Voltage
What are fuses?
Fuses are a safety measure.
How is resistivity calculated?
(Resistivity constant of material x length of material) / cross-sectional area of material.
What does MCB mean?
Miniature circuit breaker. This is a reusable fuse that works like a switch.
What is the purpose of a fuse?
Fuses are designed to protect the wiring, not people.
What is the purpose of the earth?
To protect people.
A machine is rated at 1005 watts, what would be the correct fuse for the plug?
Power = current x wattage.
Domestic power is 230 volts.
1005 watts / 230 volts = 4.4 amps of current.
A 5 amp fuse would be appropriate.
In an example series circuit, three components are connected to a 12 v battery, what will each components voltage be?
Each of the components voltage when added together will equal 12v (e.g. 4v,4v,4v or 2v,1v,9v).
In an example parallel circuit, three components are connected to a 12 v battery, what will each components voltage be?
Each component will have a voltage of 12v.
