Paper 1 circuits Flashcards
Light Dependant Resistor
A component that decreases resistance as light intensity increases.
Thermistor
A component that decreases the resistance as temperature increases
Charge
The electrons that are always in a wire (whether it is connected up to a cell or not)
Current
The flow of electrons in a wire or any conductor that happens when it is connected to a cell in a complete circuit
Voltage
The push or pull of electrons in the wire this is provided by the cell and makes the electrons flow
Electrical energy
This is carried by the current and is converted to heat and light energy in a bulb
Earthquakes
Sudden release of energy in earths crust that creates seismic waves. Seismograph used to measure the movements
Moving charge
An electric current is a movement of charge. Electric charges can move through metals because they have delocalised electrons that carry a charge
The size of current is the..
Rate of flow of charge
When electrical current flows through a resistor what is electrical energy transferred into
Heat energy
What is work done
The amount of energy transferred in a circuit depending on the amount of charge carried away, the electrons and the p.d pushing the charge around
What is power
The rate at which energy is transformed. Measure in watts
The power of a low voltage lamp
As the current increases the power also increases and so does the brightness
What happens when there’s a low resistance
The bulb was bright and had a higher current
When high resistance bulb dimmer and low current
What happens when the slider is at one end of the resistor
There is maximum resistance, this decreases the flow of charge, decreases the current and the bulb is dimmer
What slider is at opposite end
Minimum resistance which increases the flow of charge, increases the current and the bulb is brighter
The larger the resistance…
The smaller the current
Ohms law
The current through a resistor at constant temperature is directly proportional to the potential difference across the resistor.
Series circuits
The current is the same at all points in a series circuit
The total p.d of the cell is shared between the components
The total resistance of components is shared between the components
Parallel circuit
The total current through the whole circuit is the sum of the currents though the separate components
The p.d across each component is the same
How does the length of wire affect the resistance
As the length of wire increases so does the resistance. The length of wire and the resistance are directly proportional
How does the temperature of a thermistor affect its resistance
As the temperature increases, the resistance decreases. At bigger temperature the resistance decreases less for the same rise in temperature (curved graph)
How does the intensity of light affect the resistance of an LDR
As the light intensity decreases the resistance increases. By doubling the distance it more than doubles the resistance= curved line of best fit
Equation for current, charge and time
Current (A) = Charge (C)/Time (s)
I=Q/t
Equation for Energy, Charge and Potential difference
Charge (C) = Energy (J)/ Potential Difference (V)
Q= W/V
Equation for power, energy and time
Power (W) = Energy (J)/ Time (s)
P=E/t
Equation for Power, Potential Difference and current
Potential difference (V) = Power (W)/ Current (A) V= P/I
Equation for Resistance, Potential difference and current
Resistance (Ohms)= Potential difference (V) / Current (A)
R=V/I
Primary waves
First type of shock wave produced, longitudinal, move down into the earth away from epicentre. Can go through solids and liquids.
Secondary wave
Second type of shock wave produced, longitudinal, can only travel through solid
How does an LDR work
The resistance increases as the light intensity decreases
How does a thermistor work
Resistance increases as temperature decreases
How does a thermistor work in a circuit
The decrease in resistance when the temperature increases will allow a higher current so may turn on air conditioning for example
How does an LDR work in a circuit
The decrease in resistance when the brightness increases will allow a higher current e.g. closing a blind in bright light
