P1. Topic 2- Electricity 🥈 Flashcards
What is current
Flow of electric chsrge
What is potential difference
The driving force that pushed the charge around
What is the unit of current
A (ampere)
What is the unit for potential difference
V (Volt)
What does greater resistance do to the current when the potential difference is across the component
The current is smaller
What does total charge pf a circuit depend on
Current and time
Give the formula for charge
Charge= current x time
Q= IT
Give the formula for potential difference
Potential difference= current x resistance
V= IR
What is potential difference also known as
Voltage
What is an ohmic conductor
Something that has constant resistance , e.g wire or resistor
Do ohmic conductors change the current
No!
Give examples of some resistors and components that would change by using a ohmic conductors
Diode or filament lamp
What is a filament lamp
A bulb that transfers some energy to thermal energy of the filament, which is designed to heat up. Resistance increases with temperature.
What is a diode
Dependant on the direction of the current but resistance can be very high if it is reversed
What does the ammeter measure
Current
What does the voltmeter measure
Potential difference
Describe the quiptment to investigate resistance
Equipment 1.5 V cell
Ammeter
Voltmeter
Crocodile clips
Thine resistance wire
Meter ruler
Describe the method for investigating resistance
Connect the circuit
Connect the crocodile clips to the resistance wire, 100 centimetres (cm) apart.
Record the reading on the ammeter and on the voltmeter
Move one of the crocodile clips closer until they are 90 cm apart.
Record the new readings on the ammeter and the voltmeter.
Repeat the previous steps reducing the length of the wire by 10 cm each time down to a minimum length of 10 cm.
Use the results to calculate the resistance of each length of wire by using R = V/I, where R is resistance, V is
voltage and I is current.
Plot a graph of resistance against length for the resistance wire.
What kind of IV characteristic are linear components
A straight line
What kind of IV characteristic are non linear components
Curved
What would a graph of an ohmic conductor look like
Directionally proportional, linear
What would a graph of a filament lamp look like
Curved
What would a graph of a diode look like
Only flows in one direction and high resistance in reverse direction
What is a light dependant resistor
A resistor that is dependant on the intensity of light, resistance decreases when there is a bright light. Shocker.
