P2.3 Currents in Electrical Circuits Flashcards
Describe how an insulator becomes charged?
Rubbing / friction it transfers electrons.
What would happen if two positively charged objects were brought next to each other?
They would repel.
Describe (in terms of electrons and charges) what happens when a charged balloon is brought close to a wall.
Balloon is negatively charged.
It repels the electrons in the wall.
It is attracted to the positive charges left in the wall.
Define an ‘electric current’ and state what this is in metals.
The flow of charge, the flow of electrons.
What type of current do cells and batteries provide?
Direct current .
How should you put an ammeter into a circuit and what does it measure? give the units.
In series, current, amps.
What is another term for voltage?
Potential difference.
What will happen to the current if the potential difference is increased?
Increase.
How should you put a voltmeter into a circuit and what does it measure? give units.
In parallel, voltage or p.d, volts.
Name 3 compounds shown as an I-V plot?
Filament lamp.
Resistor.
Diode
Explain the effect of increasing resistance on current?
Reduces current because it is more difficult for the electrons to flow.
What p.d is needed to make a 2A current flow through a 10ohm resistor?
2x10=20V.
What happens to the resistance of a filament amp after it is turned on? How does this affect current?
Resistance increases.
Current decreases.
What happens to the resistance of a LDR as light intensity increases? What affect does this have on current?
Resistance decreases.
Current increases.
Explain what happens to a resistor as current passes through it?
Heats up because there are collisions between electrons and the ions in the lattice.
