Principles Of Electricity Flashcards
(32 cards)
What is the smallest part of any material?
Molecule
What charge are protons?
Positively charged
What charge are electrons?
Negatively charged
In an electrically neutral atom the number of …….. is equal to the number of ……….
Protons , electrons
What is the simplest atom?
Hydrogen
How many protons and electrons are in the helium atom?
2
What is electric current?
Random free electron movement
What is the resultant electron flow around the circuit called?
Electric current
What 2 ways can fractions be classified in?
Vulgar fractions and decimal fractions
What is a conductor?
Anything that allows electrons to flow
What are 4 good conductors?
Aluminium
Copper
Brass
Silver
What is 4 good insulators?
Rubber
Glass
Plastic
Diamond
What are 3 effects of an electric current?
Thermal effect
Chemical effect
Magnetic effect
How do you work out efficiency?
Output=3kw
Input =3.7kw
Efficiency = output / input x 100% = 3000 W / 3700 W x 100 = 0.8108 x 100 =
What is a single phase circuit?
1 live brown
1 neutral blue
1 earth green and yellow
What is a 3 phase circuit?
L1 brown
L2 black
L3 grey
1 neutral blue
1 earth green/ yellow
How can the magnetic flux set up by a current through a coil of wire be reversed?
Reversing the direction of the current through the coil
How many diodes are used in a full wave bridge rectifier?
4
What is the resistance of an electrical conductor directly proportional to?
Length
What volume is used to measure resistivity for a given material
1m2
What is the formula used to determine mechanical power?
Power = Mass x gravity x distance / time
What does an ohmmeter measure?
Resistance
What does an ammeter measure?
Current
What does a wattmeter measure?
Power
