Currents in electrical circuits Flashcards
Describe how an insulator becomes charged?
Rubbing / friction transfers electrons
What would happen if two positively charged objects were brought next to each other?
repel
Describe 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 charge 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 name 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 the units
In parallel, voltage or p.d., volts
Define potential difference
1 Volt is the energy transferred per unit charge/1 joule per coulomb
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 effect does this have on current?
Resistance decreases, current increases.
What happens to the resistance of a LDR as light intensity increases? What effect does this have on current?
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.
