M3.3 Flashcards
What is the potential difference?
The difference between two charged points (eg, -0.8 and -0.2 the PD is 0.6).
When does electrical voltage occurs?
As soon as there is a deficiency of electrons at one point and an excess of electrons at another point
What is the quantity of electrons called?
Electrical charge
What is the unit of current and its symbol?
The unit is coulomb and is represented by Q
How many electrons in one coulomb?
1Coulomb=6.24x(10x18) electrons
Which charge is fixed in metal?
Positive charge
What is alternating current?
A current that periodically changes its flow direction
What is better for longer distance AC or DC?
alternating current due to that you can easily use a transformer on it
What does the polarity of a circuit do?
It changes the direction of flow through the circuit
Is chemically pure water conductive?
No it is an insulator until you add salt for example
How does current pass through water?
It uses its components hydrogen and oxygen to pass through
What happens if you add direct current to a water solution?
Hydrogen will build up on the negative rod and oxygen on the positive rod
There will be 2/3 of hydrogen and 1/3 oxygen on the rod
What does a fluorescent material do inside a filament tube light?
It changes radiation into light
How does a the filament in a tube lighting protect itself from burning, vapourising, oxidising?
The glass is filled with gases like nitrogen
Why wont the molecules or atoms become one gas?
Due to heat it allows them to move around random layers without combining
Who invented the electron beam tube (Braun tube)?
K.F.Braun, German physicist
What is current measured in?
Amps
Who invented voltage?
A.Volta Italian physicist
Voltage is also known as?
Electromotive Force (EMF)
What happens when you separate positive and negative charges?
It will generate voltage
What gases are used in high capacity lamps (halogen bulbs)?
Halogens like iodine or bromine
What provides a visualisation of rapidly varying processes?
Oscillographs and oscilloscopes
What is the difference between a oscillograph and a oscilloscope?
The oscillograph can permanently recorded but oscilloscopes can only show you but not record the information
Why is the electron beam oscilloscope used today?
Because it is easy to use versatile,and shock resistant
