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Electricity

Grade 9 Electricity Unit

QuestionAnswer
What is electricity? The movement of electrons (negative). the protons (positive) never move outside of the nucleus
What is Static electricity? The build up of electrical charge (electrons on a substance or object.
What is electrostatic induction It is a method used to charge an object without actually touching the object to any charged object
What is a neutral charge? When the amount protons (positive) and electrons (negative) are equal
What is a negative charge? When the amount of electrons (negative) are higher in concentration than the protons (positive)
What is a positive charge? When the electrons (negative) are in lower concentration than protons (positive)
Which charges are unbalanced? Negative and Positive charges
What are the three laws of electrical charges? 1) opposite charges attract each other 2) like charges repel each other 3) charged objects attract uncharged (neutral) objects
What makes the voltage deadly? The current
What type of electricity does NOT allow the continuous flow of electrons> static
What is electrical current? The movement of electrons carrying through a conductor
What type of electricity is needed to operate electrical devices? current electricity
What are the two most important aspects of a circuit The continuous pathway for electrons and the energy source
What is a conductor? a material that allows electrons to pass through easily
Most often, what material is the best conductor? Metals (the best ones are copper and gold)
What is an insulator A material that resists or stops the flow of electrons
Most often, what materials are the best insulators non-metals, such as cardboard, plastic, rubber, wood, and glass
What is a semi-conductor? A material such as silicon with some ability to conduct and some insinuative qualities
What is an example of a semi-conductors Some plastics can be semi-conductors
What is a superconductor? The perfect conductor - no resistance to the electron flow
How can you make metals superconductors? Cooling them to very low temperatures
What is static discharge? Zapping - the release of electrons
What is a circuit diagram? Drawings of the pathways for electrons to flow
What kind of circuit diagrams do engineers and designers use to show components and connections clearly? Schematic diagrams
What is a circuit? The complete, continuous path that electrons flow through (along)
How many basic part of a circuit are there? 4
What are the basic parts of a circuit? Source (provides energy and supplies e, cell/battery) Conductor (provides pathway for e, wire) Switch (controls flow of e) Load (device to convert electrical energy into another form of energy, light bulb, motor)
What is a series circuit? A circuit where all devices are in a single path
How many pathways are there for electrons in a series circuit? 1
How do we know if it is a series circuit? If the pathway is broken (burnt out bulb) the whole circuit stops functioning.
Which circuit has a reduced amount of energy available? Series
What is a benefit of the series circuit? Being able to shut off all the electricity at once.
What is the definition of a parallel circuit? A circuit that has multiple pathways for electron flow (2 or more)
How can we tell if it is a parallel circuit? If an interruption occurs in one pathway, it does not affect the res of the circuit.
Does adding another pathway affect the rest of the circuit (parallel) no, it has no influence
What happens if you add a resistor to a parallel circuit? It decreases the TOTAL resistance of the circuit.
What is the definition of power? The rate at which a device converts its energy (heat, light, sound) - how fast electrical energy becomes 'useful' energy
What is the unit for Power? Watt (W)
What is 1 watt equal to? 1 J (joule)/ 1s (second)
the faster a device converts energy the ... its power rating higher
What is energy? The ability to do work (effort into something)
What is energy measured in? Joules (J)
What is a Kilowatt hour (kWh) The amount of 1000W over a time frame of 1 hour
How do you calculate voltage? Voltage (V) = Current (I) x Resistance (Ω)
How do you calculate Power? Power(W) = Voltage (V) x Current (I)
How do you calculate Energy? Energy (J) = Power (P) x Time (s) SECONDS
How do you calculate Efficiency? Efficiency (%) = output/input x 100
What are the formulas for the transformers? V1/N1 = V2/N2 and I1 x N1 = I2 x N2
What is a step up vs step down transformer? A step up transformer means that the primary coils are less than the secondary coils. A step down transformer means the primary coils are more than the secondary coils
What is energy dissipation? The spreading cut or loss through dispersion
What are the three laws about energy? 1. Energy cannot be created or destroyed 2. It does not start to exist or go away/disappear 3. Energy must be transformed from one form to another
What is the Law of Conservation of Energy? Energy cannot be created or destroyed. In any change, some energy is lost as heat
What is electromagnetic induction? The generation of electrical current by noving coils of conduction wire through a magnet
Who discovered electromagnetic induction? Micheal Faraday
What is DC? Direct Current. Electrons are moving in one direction only.
What is AC? Alternating current. The movement of the electrons back and forth through the conductor to generate current.
What device can generate AC? A magnet
What is Chemical Generation? Direct current is generated by a chemical reaction where electrons move from one ion to the other
In order for a chemical reaction to work, what 3 things do you need? Two different electrodes (metals) Electrolyte (aqueous with charged entities) Conductor/ pathway (wire)
What is a Wet Cell? A wet cell has liquid electrolyte. They have a fluid, which is free to move wherever. They are generally heavy and bulky
What is a Dry Cell? In a dry cell the electrolyte is restrained either by a container or mixed with a gel.
In a transformer, which coil is the main supply? Primary coil
In a transformer, which coil is the load? The secondary coil
What are galvanic/ voltaic cells? They are devices that use a chemical reaction to create electricity
Created by: marthavalmana