Electricity

Created by

Jay <3

Cards (71)

What is electric current? Electric current is the flow of electrical charge
What is current measured in? Amps
What is electric charge measured in? Coulombs
How can you calculate charge flow? Charge flow = Current * Time Q=It
What is the resistance of a component? The measure of how it resists the flow of charge
What happens to the charge and current, if the resistance is high? [2] - The more difficult it is for charge to flow - The lower the current
What is resistance measured in? Ohms
What does potential difference (voltage) tell us? Difference in electrical potential from one point to another.
What happens when the potential difference across a component is large? [2] - The greater the flow of charge through it's component - The bigger the current
What is potential difference measured in? Volts using a voltmeter
What is the equation for Ohms law? Potential Difference = Current * Resistance V=IR
What are V-I graphs used to show? The relationship between the potential difference and current for any component.
What does a straight line through the origin indicate? That the voltage and current are directly proportional
What does a steep gradient indicate? A steep gradient indicates low resistance
What does a shallow gradient indicate? A shallow gradient indicates a high resistance
What is an ohmic conductor and what does it show? A resistor in which the current is directly proportional to the potential difference at a constant temperature. This means that the resistance remains constant as the current changes.
What happens to the temperature as the current flows through a filament lamp increases? Increases.
What happens to the current in a diode? [2] - Current in a diode will only flow in one direction. - The diode has a very high resistance in the reverse direction.
What happens to the resistance in a Thermistor? The resistance of a thermistor decreases as the temperature increases.
What happens to the resistance of an LDR? The resistance of an LDR decreases as light intensity increases.
Electrical components can be connected in a ______ or ________ 1. Series 2. Parallel
What is the current like through each component in a series circuit? It's the same through each component.
What happens to the total potential difference supply in a series circuit? It is shared between the components
Why is the total resistance of two components the sum of the resistance of each component? Current has to travel through each component in turn.
What happens when you add resistors in a series circuit? Adding resistors increases the total resistance in ohms. Rtotal = R1 + R2
What is the potential difference like in Parallel circuits? The potential difference across each component is the same.
What is the total current the sum of in a parallel circuit? Sum of the currents flowing through the separate components.
What is the total resistance of two resistors like in a parallel circuit? The total resistance of two resistors is less than the resistance of the smallest individual resistor.
What happens when you add resistors to a parallel circuit? Adding resistors in parallel reduces the total resistance.
What does the power of a device depend on? [2] - Potential difference across it - Current flowing through it
Will a device with a higher potential difference or current use more energy per second than one with a lower potential difference or current? Yes.
What is the equation for (current)2? Power = (current)2 * resistance P = I2 R
What is a direct current supply? It is the type of current that is supplied by cells and batteries.
What is an alternating current supply? It is the type of current used in mains electricty.
What is the mains electricity in the UK? 230 volts
What is the frequency in the UK? 50 Hertz
How many cables does the main supply use? Three
What is the colour and electrical potential of the live wire? [2] - Brown - 230V Potential
What is the colour and electrical potential of the neutral wire? [2] - Blue - At o close to the 0V earth potential
What is the colour and electrical potential of the earth wire? [2] - Green and yellow stripes - 0V Potential