What is:
Ohm’s law
V=IR
Applies for ohmic conductors
What is:
Voltage
Energy per unit charge
V = E/Q
What is:
Current
Rate of flow of charge
I = Q/T
What is:
Resistance
Opposition to the flow of charge
Symbol = R
Unit = Ohm = Ω
What is the:
Effect suffered by non-ohmic non-super conductors?
- Electrons collide with stationary ions
- They vibrate and take up more space
- Causes more collisions
- Heats up
- Leads to resistance increasing (as particles take up more space and have more energy)
What are:
Series circuits
Circuits where there is only one route for current to flow through
current → all components
What is a:
Component
A part of a circuit
Characteristics of:
Series circuits
one route
current is same everywhere
pd/voltage shared by all components
What are:
Parallel circuits?
circuits with branches
DO CIRCUIT SYMBOLS
DO DIAGRAM OF V vs I FOR FILAMENT LAMP, RESISTOR, DIODE
What is:
Kirchhoff’s 1st law
Σ p.d in = Σ p.d out
∴ in series circuit, ratios can be used to calculate the p.d per component
Characteristics of:
Parallel circuits
- multiple branches/routes for current to flow
- branches can be switched off/on without breaking circuit
- battery used up faster as less resistance
- each branch has same overall voltage
- total resistance < branch with lowest resistance
What is:
Kirchhoff’s 2nd law
total current = Σ current of each branch
Rt = Vt/It
What is an alternative to:
Find resistance
Kirchoff’s 2nd law
1/Rt = 1/R1 + 1/R2 + 1/R3
What is a:
Diode
a component that allows current to flow one way only
What is:
The charge of 1 electron
-1.6 X 10^-19C
How does:
An object gain a positive/negative charge
- Friction transfers negative electrons from object A to B
- B now has more electons than protons
- it becomes negative
- (Opposite charges repel / like charges attract)
- (insert context)
What condition is needed for:
Electrons to be trapped in an object with an overall negative charge
Material to be an insulator
