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Junior Cert Science Thurs

Any predictions on the experiments coming up? or any topic coming up? Hardwater, Ohm's Law, work/pressure, and dna are common topics to come up. Also Balancing equations come up almost every year. Can anyone explain to me how they work as I just don't understand them

Emma_5811 — 15/06/16
this sheet is really helpfully you just need to learn them really
Feery — 15/06/16
Its hard to predict experiments but these ones seem to come up most often.... * To show a plant produces starch during photosynthesis (it came up in 2015 - unlikely) * Titration (Its likely to come up) * To show the presence of CO2 in air (it came up in 2015 - unlikely) * Chromatography (highly likely) * Distillation (likely) * Preparation of O2 (likely) Other possible experiments... * Seed Germination * Conditions necessary for rusting * To show CO2 is more dense than air I hope this helps :)
Cross.Phx — 15/06/16
I've got some Physics notes here. ELECTRONICS A diode is a component that will allow a current to flow in one direction only. When the positive terminal of a battery is connected to the positive end of the diode, it os called forward biased and it allows a current to flow. If its in reverse bias, it won’t flow. The code can be used as a rectifier to change a.c.to d.c. _________ LIGHT EMITTING DIODE An LED gives out light when a current flows through it. It will only flow if it is forward bias. They can only take small currents so a suitable resistor must be lined up in series to prevent from blowing the LED _________ LIGHT DEPENDANT RESISTOR An LDR is a resistor whose resistance depends on light. When light falls on it, its resistance decreases
Cross.Phx — 15/06/16
ELECTRICITY IN THE HOME Plugs have a live wire (positive) which is brown and connected on the bottom right of a plug Plugs have a Neutral (Negative) wire which is blue and is connected to the bottom left of a plug Plugs have an Earth wire which is green/yellow and is connected to the top of a plug This is a safety wire which is connected to the metal casing on an appliance and runs to a plate buried in the ground. _______________ FUSES A Fuse contains a thin piece of wire which heats up and melts when a current above a certain level passes through it Although modern houses use circuit breakers which are switches with a bimetallic strip, they switch off if they heat up due to an electrical fault. They don’t have to be replaced. _______________ MEASURING ELECTRICITY The watt(w) is the unit of electrical power. The ESB uses the Kilowatt hour (kWh). It is the electrical energy used by a 1kw appliance running for 1 hour. 1. The number of units of electricity used by a 3kW heater in 4 hours 3kilowatts x 4 hours = 12 units To calculate the cost of running an appliance, multiply the units by the cost per unit. 1. 12units x 15c = €1.80 _______________ ELECTRICAL POWER Electrical power can be calculated using this formula Power = Voltage x Current The ESB provides current at a voltage of 220V To find how much current an appliance uses Current = Power divided by voltage This can indicate what type of fuse to use, it should be slightly higher than the current. ______________ DIRECT CURRENT AND ALTERNATING CURRENT A direct current pushes the current in one direction only An alternating current moves back and forward many times per second Since a direct current is needed in some appliances and the ESB only provide alternating current since its cheaper, a rectifier is used to convert it to Direct current.
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