Y10 Autumn Term Physics Roundup Flashcards
What is Current (I)?
- The flow of charge per second
- The charges that flow in a circuit are free electrons
- Electrons are pushed away from the negative terminal of the power supply + are pulled back towards the positive terminal
What’s current measured in?
Amperes (A)
What is the symbol for a switch?
1) A line sticking out with two circles on either side (open)
2) A straight line with two circles on either side (closed)
What is the symbol for a cell?
Two horizontal lines cut off by two vertical lines with a plus sign above one of them
What is the symbol for a battery?
Same as a cell but with two extra vertical lines w/ a dotted horizontal line in between them all in between the cell symbol
What is the symbol for a diode?
A straight line with an encircled pause button type thing in the middle of it
What is the symbol for a resistor?
A rectangle with two lines coming off either side
What is the symbol for a variable resistor?
Same as a normal resistor but with an arrow coming across it
What is the symbol for a LED (light emitting diode)?
Same as a regular diode but with two small arrows pointing away from it
What is the symbol for a lamp?
A circle with a cross inside of it and two line coming off on either side
What is the symbol for a fuse?
Same as a resistor but w/ a line going all the way through
What is the symbol for a voltmeter?
A circle with a V in it
What is the symbol for a ammeter?
A circle with an A in it
What is the symbol for a thermistor?
Same as a resistor but w/ an angled line going through it
What is the symbol for a LDR?
A smaller, encircled version of the resistor symbol with two arrows pointing towards it
What’s Potential Difference (V)?
The work done (energy transferred) per unit of charge that passes through a component
What’s potential difference measured in?
Volts (V)
What’s Resistance?
How easy/hard it is for electrons (current) to flow in a material
What’s resistance measured in?
Ohms
Give some examples of resistance in appliances
Filament lamp: higher temperature, higher R
Diode: forward resistance low, reverse resistance high
Thermistor: R decreases as temperature increases
LDR: R decreases as light intensity increases
What’s Ohm’s Law?
- The current through a resistor at a constant temperature is directly proportional to the p.d across it
- An Ohmic conductor gives an I-V graph that has a straight line through the origin
What’s an I-V graph/characteristic?
A graph of current against p.d for a component.