P5 - Electric Circuits Flashcards
(47 cards)
Like charges _____ and unlike charges _______
Like charges repel and unlike charges attract
Static is formed when two _______ rub together
Insulators
The object that loses electrons becomes ________ charged and the object that gains electrons becomes _______ charged
Loses = positively charged Gains = negatively charged
When you rub a polythene rod with a duster, which or the two items becomes negatively charged and why?
Rod = negative because electrons are transferred from the duster to the rod
Describe the electrostatic induction that occurs when a positively charged balloon approaches a wall: (3)
•when a positively charged balloon approaches a wall (neutral), the electrons in the wall are attracted to the surface, creating a negatively charged surface, attracting the balloon
Why do only electrons in an atom create charge and not protons too?
Electrons are free to move and protons are stuck in the nucleus; this is why in a wall during electro static induction, electrons can be attracted or repelled but protons can’t
Why are metals good conductors of electricity?
They have free electrons that can move and carry charge
What aren’t plastics good electrical conductors?
They don’t have as many free electrons as metals so charge cannot be carried effectively
Explain the flow of charge in an electrical circuit (3)
- the cell (battery) provides energy for the electrons
- in a complete circuit, there are free electrons in al the metal components so they carry the charge around the circuit
- electrons carry negative charge so are attracted towards the positive terminal
What types of energy do bulbs produce? (2)
Heat and light energy
What is Electric Current and what units is it measured in?
The rate of flow of charge or the charge flowing per second; measured in amperes or Amps (A)
How many Amps is a Milliamp? (mA)
1 x 10^-3 of an amp or 1/1000 of an amp
What is the equation for charge, including units?
Charge/ Q (coulombs) = Current/ I (Amperes) x time/ t (seconds)
Voltage
The amount of energy needed to make the current flow
Ammeter: What is it? How is it connected?
A device used to measure current which is connected in series either side of a component
Voltmeter: What is it? How is it connected?
A device used to measure voltage which is connected in parallel to the bulb or a component
What is the unit of voltage?
Volts (V)
The larger the voltage, the _____ the current
The larger the voltage, the bigger the current
Power: what is it? What are the units?
Power is the rate at which energy is transferred and is measured in Watts (W)
What is the equation for power?
Power = Voltage x Current
What is potential difference
Another word for voltage; the different in energy per unit charge; a potential difference of 1 volt means that 1 joule of energy is transferred into or out of electrical form per unit of charge
OR
V = J/Q (energy in joules/ charge in coulombs)
Static charge
A form of electric charge which does not move
Resistance
A measure of how much a conductor opposes current
What is the equation for resistance?
Resistance = voltage / current
