Karteikarten
Magnetism
Karten in diesem Stapel (38)
- 1Types of Electricity *Static Electricity*When electrical charge gathers in one place
-created when certain materials rub against each other and some of the electrons are transferred from one material to the other
e.g. Lightning - 2Types of Electricity -Current electricityWhen electrical charge moves from one place to another
-created when electrons move from one place to another carrying electrical energy - 3Protons + ElectronsThe protons are locked in the nucleus and are not easily released from the atom. However, electrons exist in orbits relatively far from the nucleus and can be moved from atom to atom. Therefore, electrons are the particle which moves to charge an object
- 4Valence ElectronsThe ones which are most easily removed
- 5The Role of Electrons in Conduction and InsulationAtoms which have full outer shells hold onto their valence electrons more tightly than atoms which have only a few valence electrons. Atoms with full outer shells are known as non-metals, vice versa. Metals have valence electrons that are easy to remove, they are electrical conductors. Non- metals are generally electrical insulators as their valence electrons are not easily released from the atom
- 6Charging with frictionThe most common way in which electrically neutral objects become charged is by friction. Charging by friction involves two objects rubbing against each other. Electrons are scraped off one of the objects and transferred to the other object. The object that gains electrons becomes negatively charged and the object that loses electrons gains an equally positive charge. These charges are called static charge.
- 7Conservation of Electric ChargeNone of the charges have been created or destroyed.
- 8Static Electricity-Electron transfer causes static electricity
-Results from an imbalance of charges
-Can occur by induction, friction and contact.
(Conductor does not get charged this way) - 9Charging by contactPositive and negative charge
Charges are never created but are transferred from one surface to another. Charge is conserved-the total number of charges between the hand and the cloth remains constant.
*Unlike/opposite charges attract
*Only negative charges are displaced - 10Charging by inductionInduction charging charges an object without actually touching the object to any other charged object.
- 11Charged objectsCharged objects will either experience attractive or repulsive forces depending on their respective charges.
*Like charges repel
*Unlike charges attract - 12Conductors and insulators*Conductors
-Allow charges to move freely through them, eg metals (electrons repel each other and spread out).
-Any charge transferred/induced is quickly conducted away leaving the metal neutral.
*Insulator
-Insulators do not allow charges to move freely through them eg. plastics.
-Do not lose charge easily as charges cannot move freely in them - 13Uniform distribution of chargeUncharged objects, charges being balanced, and the object is neutral. The charges are distributed so that all areas of the object are neutral.
- 14Object becomes chargedWhen an object becomes charged it has an imbalance of positive and negative charges. How these charges are distributed depends on whether the object is a conductor or an insulator.
- 15Charged Conductors(-):The like charges repel each other, causing the electrons to spread evenly on the conductor's surface.
(+):The positive charges cannot move, but electrons are attracted to the positive region. This leaves behind evenly distributed positive charges on the conductor's surface. - 16Charged InsulatorsAs insulators have electrons that are not free to move, the region that becomes charged remains charged. The charges cannot redistribute around the surface.
- 17Inducing ChargeIf a charged object is moved close to a neutral conductor, the conductor's charge distribution can change, which allows the conductor to act as if it is charged.
- 18Charging by ContactWhen a charged object comes in contact with an uncharged object, the charge can be transferred from the charged object to the uncharged object.
- 19EarthingEarthing is the process whereby a pathway is provided so that excess electrons can flow to the ground or, conversely, electrons from the ground can flow to the object to cancel out any excess of positive charge.
- 20Electrical Discharge-Lightning-Updrafts and downdrafts within the cloud are thought to cause charge separation within the cloud.
-As the charge separation in the cloud and ground builds up, the air particles become ionised, providing a pathway for charges to travel down, resulting in a lightning flash.
-The cloud causes an induced charge on the ground, induced charges like to collect at sharp points and the higher the object the more likely it will get struck. - 21Series Circuits(only one path for the current)
-Current same at all places in the circuit.
-Supply voltage is shared between components in a series circuit.
-The sum of the voltage across components in series is equal to the voltage of the supply.
-The voltages across the components are in the same proportion as their resistances. This means that if two identical components are connected in series, the supply voltage divides equally across them - 22Parallel Circuit(more than one path for the current)
-Current in parallel circuit splits into different branches combines again before it goes back into the supply.
-The voltage across components is the same for each component.
-Require more wires and consume more energy per second or power. - 23Series VS Parallel-Series circuits have component linked one after the other. If one component fails, and opens the circuit, none of the components will receive any current.
-Parallel circuits have components linked to the power supply by pathways that will not open if another component fails. - 24ResistanceThe quantity that describes how much an electrical component restricts the flow of current.
- 25Ohmic ConductorsOhmic conductors have constant resistance for all voltage/current readings. As a consequence they produce linear graphs.
- 26Non-ohmic ConductorsNon-ohmic conductors change their resistance as the voltage/current changes. As a consequence they produce non-linear graphs.
- 27Resistors in SeriesR(total) = R1 + R2 + R3.......
- 28Resistors in ParallelWhen resistors are added in the parallel the total resistance decreases.
- 29When resistors are added in parallelThe total resistance drops with each additional resistor. This is because of the additional pathways around the circuit for the current to flow, making it easier for current to flow, thus decreasing total resistance.
- 30When resistors are added in seriesThe total resistance increases with each additional resistor. This is because a series circuit only has a single pathway for current, and more resistors makes it harder for current to flow, thus increasing total resistance.
- 31Power*P = E / t
*P = V I - 32Resistance in Parallel VS Resistance in SeriesIn parallel: the smaller the resistance, the brighter the bulb.
In series: the bigger the resistance the brighter the bulb. - 33MagnetsMade from magnetic materials. Metals that can be magnetised or will be attracted to a magnet, such as iron, cobalt steel and nickel.
- 34FerromagneticMaterials that can be magnetised, which are also the ones that are attracted to a magnet.
- 35Magnetic DomainsAll materials that have the ability to be magnetised contain regions.
- 36Magnetic FieldA magnetic field is a region in which a force is felt from:
-A magnet
-An electric current
-A magnetic field due to a solenoid - 37Magnetic Field Strength-Lines are close together-strong magnetic field is strong
-Lines far apart-weak magnetic field
*Field is strongest near the poles are weaker towards the centre of the bar magnet. - 38—
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- NCEA1 Physics Karteikarten am Magnetism, erstellt von Yuexin Tie am 11/11/2015.
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- Yuexin Tie
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