Electricity - Y10 Flashcards
Electric current,what direction, conventional current
Rate of Flow of electrons - positive (long) to negative (short)
P.d and Current in series
P.d = Shared
Current = Same
P.d and Current in parallel
P.d = Same
Current = Shared
Name every single formula
- Q = I t
- E = Q V
- V = IR
- E = P T
- P = V I
- P = I²R
What is p.d?
Difference of electric pressure between 2 points/ driving force that pushes the current
What is the correlation between current and voltage?
Directly proportional when the resistance is constant (and temp.). An ohmic conductor follows this graph.
What happens if you increase resistors in series?
Total Resistance increases
What happens if you increase resistors in parallel?
Total resistance decreases
What is Ohms law?
Current is directly proportional to voltage when the temp. is constant
Name 4 non ohmic conductors
- Filament lamp
- Diode
- LDR
- Thermistor
Function of diode
Current only flows in 1 direction
LDR Resistance
Dark light = high resistance, little current
Bright light = low resistance, high current
Thermistor resistance
Low temp = high resistance, little current
High temp = low resistance, high current
Resistance decreases as temp increases
Whats AC?
Alternating current is constantly changing
What is DC?
Direct current is either positive/negative and in the same direction
What is DC used in?
Cells/ batteries
Is mains supply AC or DC?
AC
Voltage and frequency for mains supply?
230V and 50 Hz
Which has a higher p.d, AC or DC?
AC
Is the p.d negative or positive in AC?
Both
Why are the 3 pins inside a plug made out of brass?
Good conductor, doesn’t rust. It’s an alloy so it’s harder than a metal
What colour is the live wire?
brown
What colour is the earth wire?
green and yellow
What colour is the neutral wire?
blue
What happens to the total current and resistance in the circuit when one resistor is removed? (PARALLEL)
- Total current would decrease
- As there are more paths for the current to pass through