Electrical Circuits Flashcards
Which direction do electrons flow?
Opposite direction to convection current
What is current flow?
AKA convection current
Direction marked on all diagrams from positive terminal to negative terminal
How does a circuit work?
Chemical reactions inside cell/battery push electrons from negative to positive terminal, but only if circuit is complete.
Why are metals good conductors?
They have free electrons
What hapens if extra bulb is added to series circuit compared to parallel?
Bulbs will get dimmer
Bulbs stay same brightness
How much current flows through each component in a series circuit?
SAME
A1=A2=A3
How much current flows through each component in a parallel circuit?
Total current taken by battery or first ammeter is sum of current through separate components
A1=A2+A3=A4
How much voltage flows through each component in a series circuit?
Supply is equal to sum of voltages across separate components
E.g. if there are 12V coming out & 3 components, V of each is 4
How much voltage flows through each component in a parallel circuit?
Same amount as supply from battery
What is resistance? What factors affect the resistance of a wire?
Opposition by a material to flow of electrical current
Length, temperature, material, cross-sectional area
How does length affect resistance?
Longer wire is, more wire to resist current
If length of wire is doubled, resistance is doubled
Resistance of wire directly proportional to length
How does temperature affect resistance?
Resistance in metal wire increases with temperature
How does material affect resistance in wire?
Lower resistance metal has, better it is at conducting, e.g. constantan & nichrome
How does cross-sectional area affect wire resistance?
Thicker wire is, smaller its resistance
If cross-sectional area is doubled, resistance will half
What is the equation for voltage?
V=IR
Voltage = current x resistance
