P2.4 Current electricity Flashcards
Explain what happens in a Van Der Graff
- The belt rubs against the felt pad
- The belt is now positively charged because the electrons have been scraped off
- The belt carries the charge to the metal dome
- The dome is now charged
- The charge transfers to the hair making it separate because the positive charges repel
When a polythene rod is rubbed with a dry cloth, how and where are the electrons transferred?
Electrons from the cloth transfer onto the atoms in the rod, which makes the rod become negatively charged and the cloth become positively charged.
When a Perspex rod is rubbed with a dry cloth, how and where are the electrons transferred?
Electrons from the rod are transferred onto atoms in the cloth, which makes the rod become positively charged and the cloth become negatively charged.
What is the equation for finding out current?
Current (amps) = change in flow (coulombs)/time taken (seconds)
What is the equation for voltage?
Voltage = current x resistance
What is the same across each component in a parallel circuit?
Potential difference (voltage)
What doesn’t change in a series circuit?
Current
How do you find the total resistance in a series circuit?
Add all the resistors together
How do you find the total current in a parallel circuit?
Add each loop together
Which path does current take in a parallel circuit?
The path with the least resistance
What does a light emitting diode (LED) do?
Current passes through it emitting light
What does a heater do?
It is designed to transfer heat
What does an indicator bulb do?
It shows the flow of electricity used as a light bulb
What does a voltmeter do?
It measures potential difference (voltage) in a circuit
What does a diode do?
It allows current through one direction
